Q&A: Need a quick pour icing recipe

The only truly “hard finish” really is royal icing. But you can do strictly icing sugar + milk + a smidge of corn syrup as a quickie icing. Kind of a mock royal icing. Will dry hard and shiny like royal icing. And you could technically pour this icing as well. Or dip cookies into the icing. And no reason you couldn’t use a butter based buttercream with an addition of meringue powder. Making the buttercream a little runnier. Icing will dry hard because of the butter and addition of meringue powder. True cookie artists would cringe from both my suggestions. But hey, they work, cause I’ve done them both. Hope this helps. ❤️

I’ve never used it for pouring over cookies, but I have flooded them with royal icing. I don’t see why you could not use royal thinned a little bit.