Step 1

Preheat oven to 350°. Heat oil in a large nonstick skillet over medium-high heat. Lightly beat eggs in a medium bowl. Stir in cheese and garlic and season with salt and pepper. When oil is shimmering, pour egg mixture into pan and cook until eggs begin to turn golden brown around the edges. Arrange tomato slices on top of egg mixture. (Some slices may sink.)

Step 2

Transfer skillet to oven and bake frittata until eggs are just set in the center, 8–10 minutes. Using a heatproof spatula, loosen frittata from pan and slide onto a warm plate. Slice and serve warm or at room temperature.