1. Arrange a rack in the top third of the oven and heat the oven to 350 F.

2. Dice 1 medium shallot. Grate 3 ounces sharp cheddar cheese on the large holes of a box grater (about 3/4 cup). Finely grate 1/2 ounce Parmesan cheese on the small holes of a box grater (about 1/4 packed cup).

3. Place 8 large eggs in a large bowl and whisk until blended. Add 1/3 cup whole or 2% milk, cheddar cheese, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper. Whisk to combine.

4. Heat 2 tablespoons olive oil in a 10-inch cast iron or oven-safe nonstick skillet over medium heat until shimmering. Add the shallot and saute until softened, about 3 minutes. Add 5 ounces baby spinach a handful at a time, and sauté until just wilted, about 2 minutes.

5. Spread the vegetables into an even layer, then pour the egg mixture over the top. Tilt the pan to make sure the eggs settle evenly over all the vegetables. Sprinkle with the Parmesan. Cook undisturbed until the eggs at the edges of the pan begin to set, about 2 minutes.

6. Transfer the skillet to the oven and bake until the eggs are just set, 18 to 20 minutes. To check, cut a small slit in the center of the frittata. If raw eggs run into the cut, bake for another minute or two. If not, then the eggs are set.

7. Heat the broiler to HIGH. Broil until the top of the frittata is lightly golden-brown in spots, 2 to 3 minutes. Let cool in the pan for 5 minutes, then slice into wedges and serve warm or at room temperature.

Recipe notes

(Sheela Prakash is a senior contributing food editor for TheKitchn.com, a nationally known blog for people who love food and home cooking. Submit any comments or questions to editorial@thekitchn.com.)

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