Prepare the seasoning: In a small bowl, mix chili powder, cumin, smoked paprika, oregano, salt, black pepper, and cayenne.
Set aside.
Cook the aromatics: Heat a large skillet over medium heat. Add oil if using. Sauté the diced onion for 2–3 minutes until softened.
Add garlic and cook 30 seconds until fragrant.
Brown the beef: Add the ground beef to the skillet. Cook, breaking it up with a spatula, until no longer pink and starting to brown, about 5–6 minutes. Drain excess fat if needed.
Season and simmer: Stir in tomato paste and the spice blend.
Cook 1 minute to toast the spices. Add beef broth and simmer 2–3 minutes until slightly thickened and saucy. Taste and adjust salt or heat.
Prep the avocados: While the beef simmers, halve the avocados and remove the pits.
Scoop out a small amount of flesh from the center to create a larger “bowl.” Chop those scooped pieces and save for topping or mix into the beef.
Make lime crema: In a small bowl, stir sour cream with lime juice and a pinch of salt. Thin with a splash of water if you prefer a drizzle.
Assemble: Arrange avocado halves on a platter. Spoon warm taco meat into each half.
Top with shredded cheese so it melts slightly from the heat.
Add freshness: Finish with cilantro, diced tomatoes, jalapeños, green onions, and the chopped avocado pieces. Drizzle with lime crema and add a squeeze of fresh lime.
Serve: Enjoy immediately while the beef is hot and the avocados are creamy.