Cooking is easily one of the most important aspects of the game:
1. It is the easiest and most efficient way of acquiring EXP.
2. It provides most, if not all, of the food served in your cafe.

To cook, press a stove or the cookbook icon. This brings up your cookbook. Pick a dish.
At this point, there should be a pot on the stove. Tap a zombie/chef and then tap the stove. Your zombie/chef should begin cooking.

Cooking a dish continues while the app is closed.

Burning a dish destroys it. The pot is blackened and can no longer be cooked. All the money spent on a dish is wasted.
The time frame for burning a dish is double the cooking time. Burning is done two ways:

1. you finish a dish, but you leave it on the stove longer than double the cooking time.
2. you stop cooking while the dish isn't ready and the time period is too long.
*It is unknown if the game waits until the very end to burn the dish or if it calculates the time at which finishing the dish is impossible.

To serve the dish, either press a zombie/cook and then tap the stove or tap the stove and then press 'serve'.
After zombies/cooks complete serving, they stand there without a task, so be sure to redirect them after serving.