½ cup crumbled reduced-fat feta cheese or shredded Parmesan cheese (2 ounces)
5 eggs, lightly beaten
¾ cup fat-free milk
Preheat oven to 350°F. Coat twelve 2½-inch muffin cups with cooking spray. Coat a 10-inch skillet with cooking spray; heat over medium. Add sausage, red pepper and onion; cook until sausage is browned. Add potatoes; cook 3 minutes, stirring frequently. Stir in oregano and black pepper.
Divide sausage mixture among prepared muffin cups (cups will be full). Top with cheese. In a medium bowl whisk together eggs and milk; pour over sausage mixture.
Bake 25 minutes or until puffed and a knife comes out clean. Cool in cups 5 minutes. Remove from cups. If desired, top with additional cheese and fresh oregano. Serve warm.
To make ahead: Place casserole cups in an airtight container and freeze up to 1 month. To serve each frozen cup, wrap in waxed paper and microwave 1 minute or until heated through.