Preheat oven to 425 degrees F. Lightly oil two 10-ounce ramekins or coat with nonstick spray.
Divide marinara sauce evenly into the ramekins. Top with eggs, milk, gruyere and Parmesan; season with salt and pepper, to taste.
Place into oven and bake until egg whites are cooked through, about 10 minutes.
Serve immediately, garnished with basil leaves, if desired.
