Simple Leek Frittata

Preheat the oven to 350°F.Combine the milk, flour, salt, pepper, eggs, and cheese in a medium bowl, stirring with a whisk. Heat the oil in a medium-sized skillet over medium-high heat. Add the leeks to the pan; cook until they are soft and lightly browned, about 3 minutes. Add garlic; cook for 30 seconds. Add the egg mixture; stir gently until the leeks are evenly distributed. Cover the pan and reduce the heat to low. Cook until the eggs are partially set, about 6 minutes.Remove the lid from the pan and bake at 350 ° F until the center is lightly browned, 10 to 12 minutes. Remove the frittata from the pan and transfer to a cutting board. Cut into 8 slices.