01 - Preheat oven to 375°F. Line a baking sheet with parchment paper or lightly grease with cooking spray.
02 - Heat a large skillet over medium heat. Add diced onion and bell pepper; sauté for 3–4 minutes until softened. Add chopped spinach and cook until wilted, about 1–2 minutes. Remove from heat and set aside.
03 - In a mixing bowl, whisk together eggs, milk, ground cumin, smoked paprika, salt, and black pepper until well combined. Stir in the sautéed vegetables.
04 - Position tortillas upright in taco shape on the prepared baking sheet. Use an inverted muffin tin or crumpled foil logs to support tortillas and keep them standing during baking.
05 - Divide egg mixture evenly among the 8 tortillas. Top each taco with shredded cheddar and Monterey Jack cheese, distributing evenly.
06 - Bake for 18–20 minutes until eggs are fully set and cheese is melted, bubbly, and slightly golden on top.
07 - Remove from oven. Top with salsa, sliced avocado, and fresh cilantro as desired. Serve immediately while warm.