It would be good not to use dark pans, it requires a lower oven temperature. Also, cooking spray doesn't do a very good job. Here's a great way to insure your cakes come cleanly out of your pans: Buy parchment paper! Cut rounds (or whatever the shape the bottom of your pan is) and place them in the bottom of your pan. Butter and flour the sides of the pans. After baking set the pans on a rack and allow the cakes to cool in the pans for 30 minutes. Then take an offset spatula or something slim and flexible like it and run it around the inside of the pans as close to the side of the pan as you can. Tilt the pan with your hand over the cake. The cake will come out of the pan onto your hand. The parchment paper will be on the bottom of the cake. You can leave it on and freeze the cake for later use, or take it off for icing right away.
