Step 1

Preheat the oven to 425 degrees.

Step 2

Add ground meat and diced onion to a cast iron skillet on medium to medium-high heat. Use a spatula to break up the meat as it cooks. Sauté until meat is browned and onion is tender.

Step 3

Meanwhile, whisk together the eggs, milk, salt, garlic powder, onion powder, ground mustard, cayenne pepper, and black pepper.

Step 4

When the meat and onion are done, turn off the stove. Spread across the bottom of the skillet so it's evenly distributed. Layer the shredded cheese, parmesan cheese, and diced tomatoes on top. Pour your egg mixture over everything.

Step 5

Bake until the center is just set, 12 to 15 minutes. Check to make sure the center isn't very wiggly and then remove from the oven. Let it rest for a few minutes before serving. The frittata will bubble a lot in the oven and settle down as it rests.