Preventing Cheesecake Cracks
Don't overbake the cheesecake. When perfectly done, there will still be a two to three-inch wobbly spot in the middle of the cheesecake; the texture will smooth out as it cools.
Cheesecake will shrink as it cools. Generously greasing the sides of the baking pan before pouring in batter will allow the cake to pull away from the pan as it cools and shrinks instead of pulling apart from the middle.
Cheesecakes have a tendency to crack, but they don't have to. This favorite American dessert can have a cracked surface for a number of reasons. One cause is air trapped inside the batter - a result of over-mixing. Once in the oven, the air bubble expands and wants to escape from the cake. As it finds its way out of the top of the cake, it creates a crack or crevice in the cake's surface. Another cause of a cracked surface is a drastic temperature change.
How to avoid cracks then? Be sure to mix your cheesecake batter well, eliminating all possible lumps in the cream cheese BEFORE you add the eggs. It is the eggs that will hold air in the batter, so add them last, and mix as little as possible once they are in the mix.
Also, be sure to cook your cheesecake gently. Use a water bath - wrap the bottom of your springform pan in aluminum foil and place it in a larger pan with water in it, just halfway up the outside of the springform pan. This will allow the cheesecake to cook more slowly and evenly.
Finally, cook your cheesecake slowly - at 325F. After about 45 minutes, turn your oven off and leave the cheesecake inside the turned off oven for another hour. Cool at room temperature with a plate or cookie sheet inverted over the cheesecake to slow the cooling. Only then can you refrigerate the cake, which you will need to do for another 6 hours at least.
If after all this, you still have a crack, make a topping or a sauce for your cheesecake, and tell all your guests that you intentionally made a special crack in the top of the cake to hold more sauce!
Bake the cheesecake in a water bath to keep the oven moisture high and the heat gentle. (A water bath is using a larger pan containing water in which to place the smaller cheesecake baking pan.)