(Image borrowed from Whiskblog.com. Yum!)
When making baked goods, recipes often tell you to butter and flour a pan - a step I often omit in favor of parchment paper. When baking a layer cake however, I will usually use parchment on the bottom, then butter and SUGAR the pan. The layer pops out without difficulty & I don't need to worry about streaks of flour besmirching my lovely cake.