While heating a large skillet over medium-high heat, combine all dry spices in a small bowl: chili powder, cumin, salt, smoked paprika, garlic powder, onion powder, dried oregano, black pepper, red pepper flakes, and cayenne pepper. Once the skillet is hot, add the ground beef and cook for 4-5 minutes, breaking it up with a spoon as it browns. The goal is to render some of the fat and develop color on the meat, which creates better flavor. Once the beef is mostly browned, add the chopped onion and cook for about 5 minutes until it begins to soften and become translucent.

Add the minced garlic to the beef and onion mixture and cook for about 1 minute until fragrant. Pour in the tomato paste and stir well to coat the meat and distribute it evenly—this helps the tomato paste caramelize slightly and intensify its flavor. Add the tomato sauce, diced green chiles, salsa, and beef broth, stirring everything together. I like to scrape the bottom of the pan to make sure all the browned bits from the beef are incorporated into the sauce, as they carry tons of flavor.

Carefully transfer the entire mixture from the skillet to your crockpot, including all the liquid and browned bits. Stir once more to make sure everything is evenly combined. Cover and cook on LOW for 6-8 hours, or on HIGH for 3-4 hours if you're short on time. The long, gentle cooking allows the flavors to meld together and the beef to become tender and infused with all those spices and aromatics. I find that LOW cooking produces the most cohesive flavor profile, even if it takes longer.

When the beef is ready, warm your tortillas and set up a taco bar with all your toppings. Spoon the seasoned ground beef mixture into each tortilla and add your desired toppings. The beauty of this dish is that everyone can customize their taco with exactly what they like.