"My favorite frittata always comes to the rescue when I have only a few staples in the fridge."
1. Preheat oven to 350°F. Lightly mist an 8-inch square baking dish with cooking spray. In a large skillet over medium heat, cook bacon until crisp, 5 to 7 minutes, stirring occasionally. Remove to a paper towel-lined plate.
2. In a medium bowl, beat eggs, milk and 2 Tbsp. water. Stir in feta, salt and pepper, half of bacon and all but 2 Tbsp. scallions.
3. Pour mixture into baking dish. Bake until almost set in center, about 15 minutes. Remove from oven; sprinkle with Cheddar and reserved bacon and scallions. Bake until center is set and cheese has melted, 5 to 7 minutes longer.