Making a quiche can be a creative process, as there are very few rules about what you can and cannot include in your quiche. The dish should contain eggs, cream, cheese and vegetables of some sort in a crust, but the rest is up to you. You can include spinach, onions, asparagus, mushrooms or any other vegetables that tickle your fancy. If you enjoy the flavor of ham, bacon, pancetta or another meat, don't hesitate to include that in the recipe as well. Determining when the quiche is done and removing it from the oven at the right time is one of the keys to making a good quiche, one that is neither dry nor runny.
Open the oven door and, using a potholder, grab the edge of the baking dish containing the quiche. Move the quiche quickly, but not too roughly, either by rapidly turning it one way then the other or by shaking it back and forth. Observe the center of the quiche as you do this. If it jiggles or appears loose, continue baking the quiche. If, however, it stays still and appears to be completely set, the quiche is done and you can remove it from the oven.
Insert a knife or toothpick into the center of the quiche, stabbing all the way down to the bottom crust. Remove the knife or toothpick, pulling it straight up out of the quiche. Examine the knife or toothpick for any signs of quiche. If the tool is covered in food -- either liquid or solid - the quiche is not yet done and you should continue baking it. If the knife or toothpick is clean, however, the quiche is done.
Stab the center of the quiche with a food thermometer and read its temperature. A finished quiche should be at least 165 degrees F, but under 185 degrees. If your quiche falls into this temperature range, it is finished and you can remove it from the oven. If it is under 165 degrees, continue baking it until it reaches this temperature.