Perfect Frittata with Zucchini and Provolone

1. Preheat broiler with rack 6 inches from heating element. Melt butter in a 10-inch broilerproof nonstick skillet over medium-high. Add scallions and 1/4 teaspoon salt; cook until tender, 2 to 5 minutes. Stir in zucchini and cook until tender, 4 to 8 minutes. (This ensures that the vegetables are cooked and won't release extra moisture, which would make the frittata tough and watery.)

2. Meanwhile, beat together eggs and milk with a fork (it gives you more speed and agility than a whisk here) until well combined. Stir in basil, 1/2 teaspoon salt, and pepper. Pour egg mixture into skillet; cook over medium-high, stirring with a spatula to create large curds, until eggs are wet on top but otherwise set throughout, 2 to 3 minutes.

3. Sprinkle with provolone, pressing about half down into eggs. Transfer to oven; broil until puffed and browning in spots and eggs are just set, 1 to 2 minutes. Let stand 10 minutes before slicing. Frittata can be served hot or at room temperature.

Cook's Notes

After adding the eggs to the skillet, use a heatproof flexible spatula to stir and push them from the edges to the center of the pan as they cook, so the liquid parts run underneath.

Variations

Earthy

1 cup sliced shallots, 3 cups sliced mushrooms, 1/4 cup chopped parsley, 3/4 cup grated Gruyere

Savory
1 cup sliced leeks (white and light-green parts), 1 1/4 cups halved cherry tomatoes, 1/4 cup thinly sliced mint, 3/4 cup crumbled fresh goat cheese

Spicy
1 cup thinly sliced onion, 1 1/2 cups fresh corn kernels, 1/4 cup thinly sliced cilantro, 3/4 cup grated pepper Jack