Preheat and prep: Heat the oven to 375°F (190°C). Grease a 9x13-inch baking dish or similar casserole dish.
Make the spice blend: In a small bowl, mix chili powder, cumin, smoked paprika, oregano, onion powder, garlic powder, red pepper flakes, and salt. Set aside.
Sauté the veggies: In a large skillet, heat oil over medium heat.
Add onion, bell pepper, and zucchini. Cook 4–5 minutes until softened. Stir in minced garlic for the last 30 seconds.
Transfer veggies to a plate.
Brown the beef: In the same skillet, add ground beef. Cook, breaking it up, until browned and no longer pink. Drain excess fat if needed, leaving about a tablespoon for flavor.
Season and build flavor: Return veggies to the skillet with the beef.
Sprinkle in the spice blend. Stir in tomato paste, drained diced tomatoes with chiles, and vinegar or lime juice. Simmer 2–3 minutes.
Taste and adjust salt if needed.
Mix the creamy layer: In a bowl, beat softened cream cheese with sour cream until smooth. If it’s too stiff, microwave the cream cheese for 10–15 seconds to soften further.
Assemble: Spread the beef mixture evenly in the baking dish. Dollop the cream cheese mixture over the top and gently spread to cover.
Sprinkle shredded cheese evenly over everything.
Bake: Bake uncovered for 18–22 minutes, until the cheese is melted and bubbly and the edges are lightly browned.
Rest and garnish: Let the casserole rest for 5–10 minutes to set. Garnish with chopped cilantro and any fresh toppings you like.
Serve: Spoon into bowls or plates. Add jalapeños, avocado, or a squeeze of lime.
Enjoy hot.