2 tablespoons butter
1 zucchini, trimmed, halved lengthwise and cut crosswise about 1/3 to 1/2 inch thick
1/4 cup chopped green onion (about 2 onions, green parts only)
1/3 to 1/2 cup roasted, peeled and chopped green chili
1 cup corn kernels (from about 1 ear)
6 eggs, gently beaten just until whites and yolks are mixed
1/2 teaspoon salt
3/4 cup grated Monterey Jack and sharp cheddar, divided
Heat broiler. Melt the butter in a 10-inch, nonstick skillet over medium heat. When butter sizzles, add the zucchini and cook, stirring occasionally. After 2 to 3 minutes, add the green onion and chili; cook until zucchini is tender, about 8 minutes. No liquid should remain in pan. Add the corn and remove from heat.
Stir the eggs into zucchini mixture with the salt and half of the cheese; stir to mix well. Return skillet to low heat, cover and cook, without stirring, until eggs have set, leaving only a top layer uncooked, about 10 minutes. Scatter remaining cheese on top and place skillet under broiler until top is browned and puffy, 1 to 2 minutes.
To unmold frittata, let it cool slightly in pan. Use a spatula to loosen it along sides, then bang it firmly on a cutting board to release underside. Slide it out onto a serving plate. Serve either hot or at room temperature. Makes 6 to 8 servings.