Heat the oil in a large skillet over medium-high heat. Add the ground beef and cook, breaking it up with a spatula, until browned. Drain off most of the excess grease, leaving about a tablespoon for flavor.

Add the finely chopped onion to the skillet with the browned beef. Cook, stirring occasionally, until the onion is softened and translucent, about 5-7 minutes.

Stir in the minced garlic and cook for another minute until fragrant. Be careful not to burn the garlic.

Sprinkle the taco seasoning over the meat and onion mixture. If using tomato paste or cayenne pepper, add them now.

Pour in the water or beef broth. Stir everything together well, ensuring the seasoning is evenly distributed and coats the meat.

Bring the mixture to a simmer, then reduce the heat to low. Let it cook, uncovered, stirring occasionally, for about 5-10 minutes, or until the liquid has mostly evaporated and the sauce has thickened to your desired consistency.

Taste and adjust seasoning if needed. Serve hot!