In a medium saucepan, heat 2 tablespoons of olive oil over medium heat. Whisk in 2 tablespoons of flour to create a roux, stirring for about 1 minute until golden. Gradually pour in 2 cups of chicken stock and 1 cup of tomato passata, mixing consistently. Sprinkle in half the spice mix and let it simmer for about 10 minutes until the sauce thickens slightly.

In a large skillet, heat 1 tablespoon of olive oil over medium heat. Sauté 1 diced onion and 2 minced cloves of garlic for 2-3 minutes until fragrant. Add 1 pound of ground beef, breaking it apart, and cook until browned. Mix in the remaining spices, 1 can of refried beans, and 1 can of black beans, stirring in a splash of sauce. Cook for another 2 minutes.

Preheat your oven to 350°F (175°C). In a baking dish, spread a thin layer of the sauce. Fill corn tortillas with the beef mixture and roll tightly, placing seam-side down in the dish.

Pour the remaining sauce over the enchiladas and sprinkle with cheese. Cover with foil and bake for 10 minutes, then remove foil and bake for another 10 minutes until cheese is melted.

Let the enchiladas rest for about 5 minutes before serving. Garnish with fresh cilantro, sour cream, or lime slices.