Mixing Cake Batter Too Much
Cake batter is one of those almost impossible things to mess up, but the most common mistake is actually over mixing it. It’s a tough dessert to destroy, but they are also the hardest to perfect, even among pastry chefs. Over-mixing and under-mixing can both affect the end result.

If you notice that your cakes end up too dense, or that they have a gummy texture, try mixing them less. Once you get all of your ingredients incorporated, it is okay to stop mixing. Unlike popular belief, lumps and bubbles in the batter won’t have a negative effect on the final cake.