Yield: 6 servings.
2 tablespoons extra-virgin olive oil
2 tablespoons unsalted butter
1 small sweet onion, diced (about ½ cup)
1 pound thin asparagus, trimmed and cut into 1-inch pieces
1 cup frozen peas
1 cup baby spinach
3 green onions, sliced
¼ teaspoon ground black pepper
1 teaspoon smoked paprika
8 large eggs
½ cup heavy cream
1 teaspoon salt
½ cup Feta cheese, crumbled
Fresh basil leaves, chopped (for garnish)
Preheat oven to 400°.
In a large ovenproof or cast-iron skillet, heat oil and butter over medium heat for 1 minute. Add sweet onion and sauté until translucent, about 3 minutes.
Stir in asparagus and cook until just tender, about 2 minutes. Do not overcook.
Stir in peas, spinach, and green onions. Season with pepper and paprika. Stir vegetables until evenly combined, allowing them to soften.
In a large mixing bowl, whisk together eggs and heavy cream until smooth. Whisk in salt. Pour egg mixture into the skillet and gently stir with a rubber spatula to distribute vegetables. Sprinkle Feta cheese evenly on top.
Bake for 20 minutes, until frittata is completely set or until edges are light golden brown and pulling away from the skillet. Remove from oven and let rest for 5 to 10 minutes.
Garnish with basil and extra Feta on top, if desired. Slice and serve.