Caprese Breakfast Casserole

Ingredients (10)

• 1 tablespoon olive oil
• 1/2 yellow onion
• 2 cloves garlic
• 18 large eggs
• 1/2 cup milk
• 1 1/2 cups shredded mozzarella cheese
• 1 cup halved grape tomatoes
• 1 cup roughly chopped basil
• 1 teaspoon kosher salt
• 1/4 teaspoon black pepper