This tutorial is the technique that I came up with that made it easier for me to make sure that I got straight even sides and a completely flat top every time I ganached a cake. The technique I came up with is kind of a mix of the upside down method that everyone knows about and the technique used by Faye Cahill where she uses two boards (one on top and one on bottom) to help ganache her cakes. My technique as I say is a mix of both and hopefully you find it helpful. There are many ways to ganache a cake, this is just my method.

Now as a preface I want to mention that depending on where you live your cake boards will differ. Here in the UK the silver boards are not the size they say they are. A 6” double thick cake card is smaller than 6” which makes it a nightmare for ganaching because it means you need to trim your cakes, which I hate doing. Because of this I have started cutting my own acrylic Perspex circles that are exactly a half inch larger than whatever cake size I am working with i.e. a 6” has a 6.5” circle underneath it. This allows for a good quarter inch of ganache all the way round the cake. You do not need to do this, if you are happy trimming your cakes then keep doing so, or if you are lucky enough to have a supplier who makes accurately sized cake boards then just use them. The rule of thumb is that you want a quarter inch gap between your cake and the edge of your board, so do whatever you need to, to get that gap.

What you will need:

2 x identically sized cake boards
A crank handled palette knife
Chocolate ganache
Cake layers
Buttercream (I use SMBC)
A large round cake drum (bigger than your cake boards – preferably a good 6” bigger)
A large turntable or a lazy susan
A bench scraper
A spirit Level

Take your cake drum and smear a little bit of ganache in the centre and place one of your cake boards on top of it making sure to keep the cake board in the centre of the drum. Push down on the cake board to make a good adhesion and allow the ganache to set so that the cake board won’t slide around on you.

Once your board is sufficiently stuck to the cake drum, smear some ganache on top of the cake board (just a little) and place your first layer of cake on top and make sure it is centred on the cake board.
Next apply some buttercream and smooth it out using your palette knife and your turntable to get it completely smooth. The more level you can make each and every layer (cake and buttercream) the easier it is going to be to get a flat top. Once you have completely filled your cake and you have your top layer of cake on, apply a crumb coat of buttercream all over the cake. Put the cake in the fridge for the buttercream to firm up before you move on to the next stage.

Take your cake out of the fridge and apply a layer of ganache on top – not too thick and not too thin, but make sure that you leave an overhang of ganache over each edge.

Take your other cake board and sprinkle one side liberally with water. Place the cake board on top of your cake (water side touching the ganache) and push down gently to adhere to the ganache.

Using a bench scraper butt the scraper up against the cake boards (using the bottom board as your guide) and make sure the top and the bottom board are perfectly aligned all around the cake. You will have to do this at several points round the cake to make sure it is completely aligned.

Once the boards are aligned take your spirit level and check to see if your cake is level – if it is not apply pressure to the top of the cake to make it level – don’t push too hard, but apply enough pressure to get a level cake.

Once your cake is level, remove the cake (including both boards) from the cake drum that it was adhered to with ganache and flip the cake over so that the top of the cake is now at the bottom. Apply some fresh ganache to the centre of the cake drum and place the cake (upside down) onto the centre of the cake drum. Scrape the ganache off the top of the cake board that used to be glued to the cake drum and then take the time to make sure the two cake boards are still aligned and level (in case there was any movement when you flipped it upside down.

Use your palette knife to apply ganache to the sides of the cake in whatever way you feel most comfortable. I tend to apply a layer round the top of the cake to secure it to the cake board and then around the base of the cake and then the middle.

What you need to do constantly, is use your bench scraper to regularly scrape around the cake so that any ganache that is too thick can be removed whilst it’s still soft – if you wait too long you run the risk of the ganache being too firm to easily scrape away and you will then have to cut the ganache away – it’s best just to regularly do a routine scrape down to get rid of any excess while it’s soft. The bonus is that because your cake boards are completely aligned at the top and bottom you can just butt your bench scraper up against both of them and you don’t need to worry that your bench scraper is straight as the two boards do the work for you.
Once you have applied your ganache and you are happy with how smooth it is leave the cake long enough for the ganache to set. Once its set remove the cake from the cake drum and flip it back up the right way and put it in the fridge.

How long you leave your cake in the fridge will come down to the size of your cake and how cold your fridge is. You need to leave it in for as long as it takes for the ganache at the centre of your top cake board to be completely and utterly firm. If you take it out too early and try to remove the top board you run the risk of the top board ripping off the ganache on top. I sometimes have to leave mines in the fridge for a good 2 hours, other times not so long.
As soon as you are sure that your ganache is completely firm all over the cake, take your cake out of the fridge and slide either a palette knife or something fairly slim underneath the top board (be careful, you don’t want to damage your ganache) and pop the top board off.

Because you applied water to the board before applying it to the top of the cake, the ganache will have seized on the top making the top board just pop right off. If you find it’s not coming off easily, put it back in the fridge until it does.
I usually find that when I take the top board off there are little gaps where there were air pockets, so take very small amounts of ganache, just enough to fill in any gaps. The less ganache you use the less likely it is you will mess up your perfectly level top. You might end up with some overhang where you’ve taken some ganache round the top edge and if so, just use your bench scraper to remove this.

Now dip your bench scraper in boiling water and use it to lightly skim the sides and top of the cake – you are not looking to really remove anything but to simply smooth down any fine lines and it also helps to seal the ganache.
You should now have a perfectly ganached cake with straight sides, a level flat top and a sharp edge to die for!! You should now leave the ganached cake at room temperature over night before covering with fondant.

Et voila!!

So anyway, this is how I go about getting sharp edges.

Basically my secret weapon as far as this technique goes is most definitely chocolate ganache – whether it be milk chocolate, dark chocolate or white chocolate. This can be achieved with an all butter buttercream like SMBC/IMBC, however it’s much easier with ganache.

To make ganache that is suitable for using underneath fondant you need only two ingredients, chocolate and cream! First things first, you need to use a specific cream. If you live in the UK, you need to use whipping cream (the one that comes in the green container), if you live in the states you need to use heavy/heavy whipping cream and if you live in Australia you need to use pure cream – basically you need something with around a 36% fat content, so whatever country you live in, just find a cream with that percentage of fat and you will be good to go.

Now onto the chocolate! When making dark chocolate ganache (which is by far the easiest to work with), it is best to use something around the 70% cocoa solid mark – I use 73% and it’s perfect. For milk chocolate I use one that has 35.6%. Milk and dark you kind of can’t go wrong if you stick with those percentages, however white chocolate is a whole different ball game. You need to find a white chocolate with as high a cocoa butter content as you can find, the higher the percentage, the firmer it will be. I switched to a more expensive white chocolate and regretted it, so it’s not all about cost! The brand I use has 30% cocoa butter.

So here are the recipes I use for my chocolate ganache – these are by weight and NEVER by volume:
Dark Chocolate Ganache: 2 parts chocolate to 1 part cream i.e. 1kg of chocolate to 500g of cream
White Chocolate Ganache: 3 parts chocolate to 1 part cream i.e. 900g of chocolate to 300g of cream
Milk Chocolate Ganache: 3 parts chocolate to 1 part cream i.e. 900g of chocolate to 300g of cream

To make chocolate ganache, I buy my chocolate in either Callets or Buttons as they are easier to melt and I put them into a plastic microwavable bowl and then cover with the cream. I then put it in the microwave on full power for 30 second blasts to start with until I can see it starting to melt, then I just do 15 second bursts. You have to be careful not to burn chocolate so just be careful. Once I have made my ganache, I cover it with clim film and let it cool down until it is at the consistency that I prefer. I prefer my ganache to be pretty soft, I prefer it to be softer than peanut butter, but only because my ganache goes firm so quickly (the joys of living in a cold climate).

For ganaching my cakes I use the upside down method – there are many ways to do this, if you google ‘upside down ganache’ or ‘upside down buttercream’ you will find several tutorials on this and you can use whichever one suits you best. This can be used for ganache or all butter, buttercream. The main things to make sure you have before you can cover with fondant is
1. A level cake – use a small spirit level to make sure
2. Straight sides – sloping sides are a no go!
3. Sharp edges on your ganache/buttercream

Here is a cake that I covered in ganache so you can see how sharp it already is before fondant:

Now, I used to keep my ganached cake refrigerated, however I just had too many problems with sweating (not me, the cakes!), so stopped it and realised there was never any need to (unless of course you have perishable filliings). I leave my cake overnight in a cool kitchen to firm up and dry. Then the next day I set about covering it. The first thing I do is brush my ganached cake with boiled water. You want enough water that you can cover every single inch of the cake (any dry spots can potentially turn into air pockets), but not too much water that the cake is soaking wet.

When it comes to fondant, I roll mines to around 2 or 3mm thick – if you are covering a dark chocolate ganache cake with white fondant, roll it to 3mm instead or you run the risk of seeing dark spots through the fondant. If your fondant is rolled to thickly, you won’t get super sharp edges, so this takes some practice.
So, cover your cake, trying to minimize air pockets – make sure that the fondant on the top and top edge of your cake is completely secure before moving down. Once you have the cake covered, take your fondant smoothers and try and smooth it as best you can. Here is where I used to pop the cake back in the fridge, but once again, I stopped that due to the sweating issue.

Now, once you’ve done this, you need to move onto the key part of achieving sharp edges and that is to use……ACETATE!!! Now I was a fool and opted to spend way too much money on 500 micron acetate, this is NOT necessary, especially if you have a hard time finding it. Any extra thick acetate will do and in Australia they use old X-Ray’s, so if you know the thickness of an X-Ray, then just find some aceate that is similar and that will do. I have my acetate cut to about 6” by 4” (that’s just a guess) – basically hand sized and I keep one sheet on the side of the cake (that sticks up past the top of the cake) and one on the top of the cake – the one on the top butts up against the one on the side and using firm pressure I slide the two round the cake together, making sure to keep them together. This action squeezes the fondant into the right angle you are creating with the acetate and forms that sharp edge. Just be careful to avoid digging the corners of the acetate into the fondant – I used a corner rounder to round the edges of mines so as to minimise this.

Some people are able to achieve the sharp edges using only fondant smoothers, however they are either magicians or I just don’t know how on earth it’s done! I’ve went from this level of sharpness with fondant smoothers (which at the time I thought was really sharp!!):

To this level of sharpness using acetate:

The acetate is also great for general smoothing too and I now find I couldn’t cover a cake without it!

Anyway, hope that has helped and if you have any questions, let me know :)