Here's Why You Should Be Smacking And Spinning Your Cake Batter
If you've ever whipped up a cake with a relatively thick batter, you'll know the struggle of endlessly tinkering with the batter in your pan to create a uniform surface. Sure, there's a good chance the dough will smooth out a bit as it bakes, but you don't want to risk having a lumpy surface or misshapen cake, so you're left doing laps with your offset spatula. However, you also don't want to let that batter sit for too long while you mess around with it.
Luckily, there's a better solution favored by many bakeries that requires less time and effort, plus you don't need to dirty any additional tools. There are a few restrictions to keep in mind, though. First, it's not the best option for delicate cakes where you've painstakingly tried to incorporate as much volume as possible, such as sponge, chiffon, or angel food cakes. And, it's also not ideal if you prefer to bake in glass cake pans. However, for most cake batters whipped up in standard metal cake tins, it's a great trick to have up your sleeve.
The smack and spin method is, well, exactly what it sounds like — you want to lift your cake pan, thwack it down on the counter, and then spin the whole pan with enough force that it disrupts the batter a bit. A few repetitions of this little movement not only allow you to get out any lingering aggression; it also smooths out that batter perfectly.
Why this trick works so well
When you're trying to smooth batter out manually, you're at the mercy of your own skill — and it can be particularly tricky if you're dealing with an oddly-shaped pan or one with a lot of small corners and crevices. The smack and spin method uses force to really get the batter into every nook and cranny, evenly spreading it throughout the pan.
Note that you do want enough room for the batter to move around in the pan, meaning your cake pans shouldn't be filled up to the very top (although they shouldn't be filled more than about halfway regardless if you want an even bake with no risk of messy overflowing).
This smack-and-spin method also has one added bonus that will level up your cakes even further. If you're an experienced baker who has tried their hand at finicky French macarons, you'll likely have done the essential step of gently tapping the baking sheet with your piped cookies in order to get rid of any air bubbles within the batter. The exact same rule applies to cake batter. While you don't technically need the level of force used in the smack and spin method just to get the air bubbles out of cake batter, it will definitely accomplish the task — and as a result, your cake will have a more even texture throughout. That's right — it doesn't just help the cake's appearance, it also improves the final product.