You've spent all afternoon baking a cake only to have the centre cave in. Or perhaps it didn’t rise to begin with, and now you have a dense, stodgy brick. Here are the four main reasons why that’s happening and how to prevent it.

1) Your leavener is expired.
Air bubbles are essential for a cake to rise, but if your leavener is stale, the chemical reaction that causes the air bubbles to form will never happen, leaving your cake dense, gummy, and flat. Before setting out to make any baked good, it’s smart to check your baking powder or baking soda for freshness, especially if you don’t bake very often.

To test baking powder for freshness, mix a small spoonful with a little boiling water. It should bubble and fizz vigorously. To see what that looks like, click here.

To test baking soda for freshness, mix a small spoonful with a splash of vinegar. The same fizzy reaction should happen. If they don’t fizz, toss them out and buy fresh containers.

2) Your eggs are too cold.
Eggs are a key ingredient when it comes to incorporating air into a batter, and room-temperature eggs will whip up far more readily than cold ones. In fact, in all our Canadian Living baking recipes, we assume all eggs are used at room temperature.

Before you start making a recipe, be sure to take your eggs out of the fridge first and let them stand while you collect all your other ingredients (30 minutes is usually long enough, depending on the temperature of your kitchen).

In a pinch, place your eggs in a bowl and pour very warm water over them to cover. Let stand until the eggs are no longer cold to the touch, about 5 minutes.

Pro tip: If your recipe calls for the eggs to be separated, do it while they're still cold and then let the yolks and whites stand separately at room temperature for 20 to 30 minutes before using. The membranes of a room-temperature egg are much more delicate than a cold one, so you’re way less likely to break the yolk if you separate them while they're still cold.

3) You under-baked the cake, or peeked while it was baking.
That old adage about not making any loud noises while a cake is baking is true! The structure of a half-baked cake is very delicate and anything from a loud noise to a drastic drop in temperature (i.e. opening the oven door to peek) can cause it to fall.

It’s easy to tell if a cake is under-baked: If it’s high and fluffy around the edges, but fallen, dense and gummy in the centre, it needed more time. To avoid under-baking your cake, check it for doneness no sooner than 5 minutes before it’s supposed to be done. To do so, insert a cake tester in the centre—it should come out clean. You can also gently tap the top with your finger. If it feels firm and springs back, it's ready.

Pro tip: Unless directed, don’t try to remove a cake from the tin straight out of the oven — it can sometimes be a bit too delicate at this stage. Let it cool on a rack for 10 minutes, then remove it directly to a rack to cool completely.

4) There isn’t enough flour in your recipe.
This one is a bit trickier and only really happens when you’re adapting another recipe or playing around with recipe development.

A cake relies heavily on protein—in eggs and flour—to maintain its structure. The protein in flour is called gluten. Gluten is a bit of a four-letter word lately, but it serves an important purpose: over-develop gluten and you’ll end up with a doorstop; avoid it entirely and your cake will likely fall.

If you don't have enough flour in a recipe, there won't be a strong enough foundation to allow for proper expansion and the cake will collapse. You’ll notice gluten-free and flourless cakes are often sunken in the centre, and that's why.

If you're trying out your own cake recipe and the texture is gummy, or the centre is fallen no matter how long you bake it, try increasing the flour by a tablespoon or two until you get the desired consistency.

Remember that a sunken cake isn't the end of the world. Most of the time, it will still be delicious and you can cover up that fallen centre by piling it with some creative toppings, like whipped cream or sweetened mascarpone and fresh fruit.

The important part is to get into the kitchen and have fun! Everyone will love your efforts, regardless.

For a collection of 25 Tested-Till-Perfect chocolate cakes and cupcakes, click here!