Cakes Have Excessive Shrinkage (excessive pulling away from the sides of the pan): The oven temperature may be too high. The baking time may be too long. The pans may be too close to each other or too close to the oven walls.
The edges pull away
Once your cake nears the end of the bake time, peer through the oven window and check the edges of the cake. When your cake is done, the sides will have pulled away from the pan slightly. The edges of the cake are the first part to set and become fully baked.
Crumble or cube the cake and spread in a single layer on the prepared baking sheet. Toast until the cake crumbles or croutons are dry and crisp. Let them cool completely and store in an airtight container for a few days. Now go crazy and use those crumbles to top ice cream, yogurt, or cupcakes.
Let the cake cool.
It should spend at least twenty to thirty minutes on your cooling rack or countertop before you even attempt to remove it from its pan. Place the cake in your refrigerator to speed up the cooling process if necessary.
Wait until your cake is fully cooled before removing it, this may take 2-3 hours. Run a butter knife or a palette knife around the inside edges of the cake tin. Get a cooling rack. Pop a clean tea towel over the tin, put your hand on top of the cake and turn it upside down onto the cooling rack.
The leavening agent is the ingredient that helps the cake to rise. Too much baking powder or baking soda can create excess gas in your cake, making it expand too quickly without the proper structure, only to deflate once you take it out of the oven.
Overbaking your cake is probably one of the most common reasons why cake can be crumbly. When a cake is overcooked, the moisture has evaporated and all that is left is a dry, overcooked sponge. This is why it's so important to keep an eye on your cake and not let it bake for too long.
Make sure you follow the recipe's instructions carefully. Cakes typically bake between 325 to 450 degrees F (see chart with Tip #9). Most convection ovens require lowering the temperature by 25 to 50 degrees F, as well as turning off the fan.
Use a cake tester
Try pricking the cake in the centre and on all sides and if it comes out clean, with a few moist crumbs, it's likely done. If the toothpick comes out totally clean, your cake might be overcooked.
too much leavener (baking powder or baking soda): think about it, the more leavener you have, the more gas will form inside the cake, and if there isn't a growing structure to support all that extra gas, the gas will escape. The cake will rise up and then collapse back down.
Cut the cake open.
Let your cake cool for about twenty minutes or so and then use a serrated knife to gently cut horizontal layers through it.
For a clean release, grease, flour—and parchment—are key. It may sound like overkill, but the most effective way to ensure that a cake releases cleanly from a baking pan is to grease the pan, line it with parchment paper, and then grease and flour the parchment and pan sides.
Before You Start
Attempting to spread frosting onto warm cake layers is a recipe for sloppy disaster. Chill your cake layers for at least 2 hours, or better, overnight. If you've made your frosting ahead, make sure it's at room temperature before you start.
Under-cooked Cake Layers
It is one of the most typical reasons why do cakes sink in the middle. If you take your cake out of the oven before the centre is done, it will sink as it cools. On the other hand, if the cake isn't fully baked through, the centre doesn't have a chance to set, and it will sink also.
Cooling cakes
Recipes will usually give instructions for cooling but as a general rule, most sponge cakes are best left for a few minutes and then turned onto a cooling rack to avoid soggy edges. Rich fruit cakes are better cooled in the tin.
This is a common mistake, and can cause your cake to collapse because the rush of cold air stops your caking from rising. Leave the oven closed for at least 3/4 of the cooking time, and then when you do check the cake, if it still needs more baking wait at least 5-10 minutes before opening the oven again.
Make sure that your warm cake is given at least 10 minutes to sit in the pan after it is taken out of the oven. This rule applies as the first step to any cake cooling method.
You must do this as soon as they are out of the oven, otherwise your cakes will definitely get soggy. Immediately following, cover the cakes tightly with plastic wrap and put aside to cool. If you have a bad recipe or have over-baked your cakes, this will not rescue them from being doomed to dry-ness.
Follow this tip: If your cake needs to be trimmed, or if you plan to torte it by cutting it into thinner layers, never do this while the cake is still warm. Wait until the cakes have cooled completely, or for the best results, chill the layers before trimming.
Cool Cakes Are Easier to Decorate
The other reason to wait is that if the cake is too hot, your icing won't stay put, and will melt into the cake. And no one likes a runny cake!
That's right, you won't be frosting your cake at room temperature; a chilled cake is essential before applying any frosting. "This step is the most important. Not chilling the cake will result in a non-straight cake. It can be lopsided, or even fall," explains Smith.