Preheat oven to 375 degrees. Line a regular nonstick muffin tin with a slice of prosciutto in 12 tins. If your slices are smaller line more than one to make a cup.
In a medium bowl, whisk the eggs. Stir in the cheese, onion, sausage, and garlic powder.
Divide mixture evenly in the cups. They should be about halfway full. Bake for 13-15 minutes until egg is puffy and center is set.
CAN THESE BE MADE AHEAD OF TIME?
Yes. You can make these egg cups ahead of time and reheat them in the microwave for 30 seconds or in the oven at 375 degrees for 5 minutes.