It seems like such a hassle when a recipe calls for buttering (or greasing) and then flouring a cake pan. And when the author also mentions lining the pan with parchment, that's yet another step to add to the list of things that need to be done to get that cake in the oven. Are all these precautions really necessary?
To Grease or Not to Grease: It Depends on Your Recipe
In short, whether or not you have to grease (or grease and flour) your cake pan really depends on the recipe you are making. If you are baking an angel food cake, or a cake that gets its rising power from an egg white foam, you don't grease the pan, for one reason: Egg white foam cake batters rise better when they have a surface that they can grip onto and essentially climb up, like the ungreased walls of a cake pan.
On the other hand, it's best to grease cake pans when you are making butter cakes (or most fat-based cake recipes). These generally take advantage of chemical leaveners (baking soda and/or baking powder) to rise as they bake, and are not as dependent on gripping the sides of the pan as they rise.
What About Flouring a Cake Pan After It's Greased?
Coating a greased cake pan with a thin dusting of flour creates a barrier between the grease and the cake batter, which prevents the grease from melting and disappearing into the batter as the cake bakes, allowing it to do its job in the end, after the cake is baked. (Essentially, the cake will slide out of the pan without a hitch.) However, flouring a cake pan after you've greased it is not absolutely necessary, and some bakers opt to simply grease their cake pans because the flour can contribute to a thicker, drier crust on some cakes, which some consider unpleasant.
Still, there are cases when flouring a pan is essential, like when your recipe has a high sugar content which, as the cake bakes, will lead to caramelization on the edges. The caramelized cake edge may cling to the sides of the pan and become glued — in this case, flouring the cake pan after it's greased is essential, especially if you have to let the cake cool in the pan before unmolding it. I'd also recommend carefully greasing and flouring bundt pans, because bundt cakes can be especially tricky to unmold from intricate bundt pans.
Parchment Is Always a Good Idea
If the sides of your cake stick, you can thankfully always run a knife around the edge to loosen them, but if the bottom of your cake gets stuck, you are pretty much out of luck. Rather than struggling to get the cake out whole, I suggest frosting the cake in the pan and then serving it from the pan, by the slice, with the help of a spatula. Next time, a round of parchment will help you avoid this unfortunate situation altogether.
When do you grease and flour your pans, and when do you skip that step? Or do you have recipes that you know you can get away with just greasing the pan?