Preheat the Oven: Start by preheating your oven to 375°F (190°C).
Cook the Beef: In a large skillet, heat the olive oil over medium heat. Add the diced onion and minced garlic, sautéing until fragrant. Add the ground beef, breaking it apart with a spoon, and cook until browned. Drain any excess fat.
Season the Beef: Stir in the chili powder, cumin, paprika, salt, and pepper. Mix well to coat the beef evenly.
Layer the Casserole: In a baking dish, spread a thin layer of enchilada sauce. Add the cooked beef mixture, followed by dollops of sour cream. Sprinkle a generous amount of shredded cheese (jack cheese and Mexican blend cheese) on top.
Bake: Place the casserole in the preheated oven and bake for 20-25 minutes, or until the cheese is melted and bubbly.
Garnish and Serve: Remove from the oven and let it cool for 5 minutes. Garnish with fresh cilantro or green onions if desired. Serve warm and enjoy!