How do I stop this from happening?
what steps do you take to shape it?
wrap warm cake in clean dish towel as soon as taken from sheet pan, let cool in spiral at room temp?
wrap filled cake in foil, cling film or parchment paper once it is filled and let shape in fridge (if dairy), freezer (if ice cream), room (if none of above filling)?
PS I find the first two help me get a good shape for final cake.
Overbaking the cake layer can cause problems. The top surface won't brown like a "normal" thickness cake when done.
like Nancy said. As soon as it comes out of the oven, invert the pan on a tea towel over which you have sifted confectioner's sugar (or cocoa if chocolate cake), peel off the parchment paper. Be sure to cut off the crisp edges (about 1/8th inch) on each of the 4 sides using a serrated knife, (to keep it from cracking), then roll up together with the towel, place on a rack, with the seam of the towel down, to cool completely. When cold, spread the filling and re-roll (lift the towel edges to roll it into shape, not too loosely). When finished, I wrap it airtight in plastic wrap and chill (because I fill with whipped cream). Keep the seam side down. I use a serrated knife to cut the servings.