Preheat your oven to 350 degrees. Coat a six cup muffin pan with nonstick cooking spray.
If using vegetables I like to precook them in a skillet as we don't like our vegetables crunchy.
Whisk together the eggs, half and half and salt in a medium bowl, then evenly distribute the egg mixture among the muffin cups.
Add about 2 tablespoons of mix ins to each cup and then sprinkle with cheese.
Bake the omelets until they are puffy and the edges are golden brown, about 20 - 25 minutes. If necessary run a butter knife around the edge of each one of the omelets to loosen them before removing them from the pan.