My first question is which sugar lace are you using or are you making your own? If it’s dry and brittle it has probably been baked for too long at too high a temperature. You can try to save it by putting a damp cloth over the brittle but not yet broken lace. After half an hour it might be OK. If you are using a name brand, I suggest contacting them. That stuff is VERY expensive and they should give you the proper guidelines. If you are making your own (I make my own cream) then I suggest baking at 70 degrees C for just 5 minutes. Take it out, let it cool, add a second layer and bake for just another 3 minutes. It probably won’t be set yet, so just leave it undisturbed at room temperature for as many hours as it takes (sometimes over night — depends on the humidity) until the edges can be separated easily from the mat. Hope this helps :)
The Garden Baker