Asparagus Feta Frittata

1 tablespoon butter

1/2 cup chopped green onion

2 cups chopped fresh asparagus

8 large eggs

1/2 cup feta cheese, divided

1/2 cup grated Parmesan cheese, divided

1/2 teaspoon sea salt

1/4 teaspoon black pepper

Preheat broiler.

 Heat oil in a large oven-safe skillet over medium; add onion and cook until softened, stirring occasionally, about 5 minutes. Add asparagus; cook until softened, about 3 minutes.

Meanwhile, whisk together eggs, 1/4 cup feta cheese, and ¼ Parmesan cheese in a large bowl; add salt and pepper and mix well.

 Add egg mixture to skillet; stir gently and cook until almost set. Top with remaining 1/4 cup feta and 1/4 cup Parmesan cheese; place under broiler. Cook until mixture is puffy and golden, about 4 minutes.

 Remove from heat; cool slightly, cut, and serve.