01 - Preheat oven to 375°F. Line a baking sheet with parchment paper or lightly grease it.
02 - Heat a skillet over medium heat. Add onion and bell pepper; sauté for 3–4 minutes until softened. Add spinach and cook until wilted. Remove from heat and set aside.
03 - In a bowl, whisk together eggs, milk, cumin, paprika, salt, and pepper. Stir in the cooked vegetables.
04 - Arrange tortillas upright in the shape of a taco on the prepared baking sheet. Use an inverted muffin tin or crumple foil logs to help them stay upright if needed.
05 - Spoon egg mixture evenly into each taco. Top with cheddar and Monterey Jack cheese.
06 - Bake for 18–20 minutes until eggs are set and cheese is bubbly and slightly golden.
07 - Remove from oven. Garnish with salsa, avocado, and cilantro as desired. Serve immediately.