Egg White Frittata with Beet Greens

• 2 tbsp olive oil
• ½ yellow onion, chopped
• 2 cups (100

Preheat the oven to 375°F (190°C).

In an ovenproof frying pan, warm the olive oil over medium-high heat. Add the onion and cook, stirring often, until softened, about 6