1 tbsp cream or milk
2 tsp minced fresh oregano, plus more for garnish (optional)
Kosher salt and freshly ground pepper
1 tbsp extra-virgin olive oil
2 medium tomatoes, diced, plus more for garnish (optional)
H cup (2H oz/75 g) feta cheese, crumbled, plus more for garnish (optional)
1H cups (1H oz/45 g) firmly packed baby spinach
Makes 4–6 servings
Preheat the oven to 425°F (220°C). In a bowl, whisk together the eggs, cream, 2 teaspoons oregano, and a pinch each of salt and pepper.
Warm the olive oil in a 10-inch (25-cm) ovenproof nonstick frying pan over medium-low heat. Add the egg mixture and cook, stirring gently, until the eggs begin to set but do not begin to scramble. Gently stir in the 2 diced tomatoes, the 1/2 cup feta, and the spinach. Cook the eggs, undisturbed, until they begin to set around the edges, 2–3 minutes more. Transfer the frying pan to the oven and bake until the eggs are set around the edges and just firm in the center, about 5 minutes more.
Loosen the sides of the frittata with a spatula and hold a platter over the top of the pan. Holding the sides with hot pads, invert the frittata onto the platter. If desired, garnish the frittata with extra diced tomatoes, oregano, and feta. Cut into wedges and serve warm or at room temperature.