Using a sheet pan is an easy way to bake up a tender and delicious frittata for a crowd or to get plenty of leftovers. This hearty one is full of summer squash, sweet pepper, and tomatoes and seasoned with chives and melty cheddar.
4 sprays cooking spray
1½ cup uncooked zucchini, thinly sliced (from about 2 medium)
1½ cup yellow summer squash, sliced, thinly sliced (from about 2 medium)
1 cup grape tomatoes, halved
1 medium sweet red pepper, cut into thin strips
½ cup 2% reduced-fat milk
1 tsp Kosher salt
½ tsp black pepper
½ tsp dried thyme
12 large eggs
¾ cup reduced-fat sharp cheddar cheese made with 2% milk, shredded
¼ cup chives, chopped
Preheat the oven to 400°F. Coat a large (18-by-13-inch) sheet pan with cooking spray.
Combine the zucchini, squash, tomatoes, and bell pepper on the prepared pan and spread into an even layer, avoiding overlap as much as possible. Bake at 400°F until the vegetables are crisp-tender, about 15 minutes.
Reduce the oven temperature to 350°F. In a large bowl, whisk the milk, salt, black pepper, thyme, and eggs. Fold in the cheese and chives. Pour the eggs over the vegetables on the pan, stirring to redistribute the cheese and chives if necessary.
Bake at 350°F until the eggs are set, 15 to 17 minutes. Run a thin knife or offset spatula around the edges of the frittata to loosen it from the pan. Store the frittata in the refrigerator for up to 5 days or freeze for up to 1 month.