Caramelized Onion Frittata

makes 4 servings
recipe adapted from Real Fast Food

• 1 lb. onions, finely sliced
• 4 tablespoons olive oil
• 6 large eggs
• a large handful of fresh parsley, roughly chopped
• 1/2 cup grated Parmesan cheese
• salt 
• freshly ground black pepper
• a heavy pinch red pepper flakes
• 1 tablespoon butter

Cook onions in olive oil in a 10-inch skillet over medium-high heat, stirring occasionally until the onions are golden and tinged dark brown, about 15 minutes. Set aside to cool. 

Crack the eggs into a bowl. Stir in onions from the pan into the eggs. Season with parsley, Parmesan, salt, pepper and red pepper flakes and stir until well combined. 

Wipe pan clean. Melt butter in skillet. Transfer egg mixture to skillet and cook on the lowest heat setting until the frittata has set on the base but the surface is still runny, about 15 mintues. Place the pan under a preheated broiler to set the surface, about 4-5 minutes. Loosen with a metal spatula and then slide frittata onto a plate or cutting board. Cut into wedge and serve.