This fluffy frittata is filled with the flavors of bacon, cheddar, and parmesan. It's so easy to make! Serve to guests for brunch, whip it up for meal prep, or enjoy it with family on the weekend.
Add diced bacon and onion to a cast iron skillet on medium to medium-high heat. Use a spatula to stir as it cooks. Sauté until bacon is cooked through and onion is tender.
Add minced garlic to skillet and sauté until garlic is golden in color, about one minute.
Meanwhile, whisk together the eggs, milk, salt, ground mustard, cayenne pepper, and black pepper.
When the bacon, onion, and garlic are done, turn off the stove. Spread across the bottom of the skillet so it is evenly distributed. Layer the shredded cheese, parmesan cheese, and spinach on top. Pour your egg mixture over everything.
Bake until the center is just set, 16 to 20 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 may bubble a lot in the oven but will settle down as it rests.
Notes
If using turkey bacon add a little oil to the skillet with the diced bacon and onion since it's so lean. This will help prevent sticking and get some crispiness.