In an oven that's too hot, the outside of the cake cooks at a much faster rate than the inside. A crust forms early on, but as the inside of the cake continues to cook and rise, this crack crusts. You might experience the same problem if the cake recipe has too much leavener or if you've used a pan that's too small.
In the case of our red velvet cake, we veered away from the original recipe: Instead of baking the cake in two 8-inch pans, we poured all the batter in one 10-inch springform pan. This meant that the cake batter was deeper in the pan, which increased the chances that the crust would form before the insides of the cake were even close to being cooked.
So what can you do the prevent this problem?
Make sure your oven is at the right temperature. Get a thermometer; make sure it's accurate.
Use the appropriate-sized pan.
To encourage even cooking (let's say you are adjusting the recipe to a different size pan, you daredevil), some bakers recommend adding another pan, filled only with water, to the oven along with your cake. The water will steam and cause the cake to cook more evenly.
If your quick breads are cracking (...and aren't they always?), you can create a shallow furrow in the batter with a spoon before sending the loaf into the oven. You'll end up with a more orderly line down the center of the loaf.
Avoid opening and closing the oven during baking, as this can cause the temperature to fluctuate.
And if you do end up with a badly cracked cake, take assurance in the fact that it will probably still taste good (our red velvet did) and that you can always make a trifle:
A (former) student of English, a lover of raisins, a user of comma splices. My spirit animal is an eggplant. I'm probably the person who picked all of the cookie dough out of the cookie dough ice cream. For that, I'm sorry.