Preheat your oven to 400°F.
Heat a pan over medium to high heat. Add the ground beef and cook until the beef is not pink anymore. Make sure to break it up while cooking.
1 lb. ground beef
Once the ground beef is cooked add all the spices and stir.
2 tsp ground cumin, 2 tsp dried oregano, 1 tsp cayenne pepper, 1 tsp garlic powder, 1 tsp onion powder, 1 tsp paprika powder
Add the tomato paste, mixing it in and cooking for an additional 1 to 2 minutes (this will remove bitterness from the tomato paste).
2 tbsp tomato paste
Pour the tomato puree into the pan, stir again, and cook for 1-2 minutes.
1 cup tomato puree
Put all the taco shells in a casserole dish and fill them with the ground beef mixture, adding 1 to 2 tablespoons each.
12 taco shells
Top with the grated cheese and bake for 10 to 15 minutes until the cheese is melted.
1½ cups grated cheese
Serve immediately with toppings of your choice (sour cream, salsa, avocados, cilantro, tomatoes, lettuce, beans, corn, etc.)