You don't want that layer cake to be crumbling, tumbling or leaning to one side. Here's what to fix!
10 Common Mistakes People Make When Baking a Layer Cake

There’s nothing like celebrating with a homemade, showstopping layer cake—it’s a true labor of love! Whether you’re a layer cake pro or about to tackle your first, avoiding these common mistakes can help make your cake picture-perfect.

Mistake #1: Not greasing the cake pan
Avoid that dreaded sinking feeling when your cake sticks to the pan by properly greasing. Line the pan with parchment paper to ensure the bottom won’t stick and comes out cleanly, and then grease with either butter and flour or nonstick baking spray.
Follow these step-by-step instructions for a properly greased pan.

Mistake #2: Unevenly distributing batter in pans
Unlike a sheet cake, layer cakes require you to evenly distribute the batter between multiple pans so that your final cakes are perfectly even. When you pour the batter, start by eyeballing it, and then pull out your trusty kitchen scale to make sure it’s even.
On the fence about getting a digital scale? Here are four reasons you need one.

Mistake #3: Not cooling layers properly
Baking can require a lot of patience, especially when it comes to cooling your cakes. Let your cakes cool in the pan set on a wire rack for 10 minutes. Then, loosen the sides of the cake with a dinner knife, place a cooling rack on top of the pan, and swiftly turn over so that the cake falls out of the pan.

Mistake #4: Stacking uneven layers
It’s likely your cakes will come out of the oven with a rounded or domed top. Avoid a lopsided cake that could fall over by trimming your layers so they’re flat. Use a serrated bread knife to gently trim the rounded part off. Instead of starting at the edge of the cake, try to only slice off the domed part to preserve as much cake as possible.

Mistake #5: Trimming warm layers
Don’t try to trim or otherwise cut your cake layers before they’re completely cooled. You don’t want to trim a cake only to have it sink in the middle!
Keep the scraps—you can use them to make cake pops.

Mistake #6: Breaking the top layer during assembly
Don’t let cake assembly scare you. You can avoid breaking the top layer when building your cake by popping it into the freezer—it’ll help ensure the layer is stable. If you’re short on time, use a spatula to gently lift the top layer onto the bottom.

Mistake #7: Frosting warm layers
We can’t say it enough: don’t skip cooling your cake layers! Frosting a warm cake will result in a big mess. If you think you’ll be short on time, try baking the layers the day before you decorate.
Speaking of frosting, do you know which buttercream frosting is best for your cake?

Mistake #8: Forgetting the crumb coat
Here’s an old baker’s trick that will help ensure a showstopping finish. Spread an even, thin layer of frosting on the cake, then pop it in the refrigerator and chill for 15 minutes before applying your final layer of frosting. This crumb coat seals the layers and prevents errant crumbs from peeking through.

Mistake #9: Using a leaky filling without a border
If you choose a leaky filling, like a jam, fruit puree or pastry cream, you’ll need to create a border to prevent the filling from leaking down the sides of your cake. Use your frosting to pipe a circle along the edge of your bottom layer before adding your filling. Voila! No mess.

Mistake #10: Forgetting to wipe your knife while cutting the cake
The best part of a layer cake? Cutting it to reveal the perfect layers. If you’re serving up your cake at a party and want picture-perfect pieces, clean your cake knife between cuts. If that doesn’t work, try running the knife under warm water and drying before each cut.