Preheat your oven to 375°F (190°C).
Heat a tablespoon of olive oil in a large skillet over medium heat. Add the chopped onion and garlic and cook until softened, about 5 minutes.
Add the ground beef to the skillet and cook until browned, breaking it apart with a spoon as it cooks. Drain any excess fat from the skillet.
Stir in the salsa, green chilies and taco seasoning, cook for another 2-3 minutes.
In a mixing bowl, whisk together the eggs, milk or cream
Pour the egg mixture over the beef and vegetable mixture in the skillet. Sprinkle the shredded cheese evenly over the top.
Bake for 20-25 or until the frittata is set.
Once cooked, remove the skillet from the oven and let it cool for a few minutes before slicing.
Serve the frittata warm, with a drizzle of avocado ranch and optional toppings such as avocado slices, cherry tomatoes, jalapenos, sour cream and chopped cilantro.