This is a master recipe, so do with it as you like. Any kind of cooked meat works well. Or none. I made mine with 1/2 pound cooked sausage and chives. I layered the add-ins before pouring in the egg mixture, as it was easier to divide evenly. Recipe doubles or triples well. Don't omit the baking powder. It gives just the right amount of lift. Yield will depend upon size of muffin tins.
5 large or extra large eggs
1/2 cup milk
1/2 teaspoon baking powder
Salt and pepper
1-1/2 cups to 2 cups shredded cheese
Good add-ins: 1/2# cooked sausage or bacon, crumbled, handful of chopped chives, frozen spinach, thawed & drained well, sautéed onions, leeks, mushrooms, etc.
Preheat oven to 350. Beat eggs, milk, baking powder and salt & pepper together.
Spray 6-8 muffin tins really well, since the egg mixture tends to stick.
Divide cheese among muffin tins along with other add-ins before pouring base mixture on. Check after baking 20 minutes. Toothpick inserted in center should come out clean, but don't overbake.
Can be baked up to a day ahead and microwaved gently to rewarm, or in 350 degree oven, covered, until hot throughout.