I'm planning on making a Swiss roll. This is a sponge cake, baked in your baking sheet (so it's thin) and you roll it up, mostly with a filling.
While looking for a recipe, some recipes say to use the same recipe as for a regular sponge cake, but add some melted butter. Other recipes don't mention melted butter and stick to eggs, sugar and flour. I'm wondering what the function of the butter is in a Swiss roll. Does it help with rolling? Or is it just taste? Can I omit it?
(I would omit it if it's just the taste. My filling will be butter cream.)