Step 1: Heat olive oil in a large skillet or Dutch oven over medium-high heat. Add the ground beef and cook, breaking it up with a spoon, until fully browned and no pink remains. Drain any excess grease.
Step 2: Reduce heat to medium. Add the chopped onion and bell pepper to the skillet with the beef. Sauté for 5-7 minutes, until the vegetables soften.
Step 3: Stir in the minced garlic, chili powder, cumin, smoked paprika, oregano, and salt and black pepper to taste. Cook for another minute, until fragrant.
Step 4: Pour in ½ cup of enchilada sauce (from your total amount) and ¼ cup of water or beef broth. Bring to a simmer and let it cook for 5 minutes, allowing the flavors to meld and the liquid to be absorbed. Remove from heat and set aside.
Step 5: Preheat your oven to 375°F (190°C). Pour about 1 cup of the remaining enchilada sauce into the bottom of a 9×13 inch baking dish, spreading it evenly.
Step 6: Prepare your tortillas. If using corn tortillas, quickly dip each tortilla into warm enchilada sauce (you can heat a small amount in a shallow dish) or lightly warm them in a dry skillet for 10-15 seconds per side to make them pliable. If using flour tortillas, simply warm them for a few seconds in a dry skillet.
Step 7: Lay a softened tortilla flat. Spoon about 2-3 tablespoons of the beef filling down the center. Sprinkle with about 1 tablespoon of shredded cheese.
Step 8: Tightly roll the tortilla and place it seam-side down in the prepared baking dish. Repeat with the remaining tortillas, beef filling, and a portion of the cheese, arranging them snugly in a single layer.
Step 9: Once all enchiladas are in the dish, pour the remaining enchilada sauce evenly over the top, ensuring all enchiladas are well coated.
Step 10: Sprinkle generously with the remaining shredded cheese.
Step 11: Bake for 20-25 minutes, or until the cheese is melted and bubbly and the enchiladas are heated through. For a slightly browned top, broil for the last 1-2 minutes, watching carefully.
Step 12: Remove from oven and let stand for 5-10 minutes before serving. Garnish with optional fresh cilantro, diced red onion, or a dollop of sour cream. Serve hot.