In a large skillet, heat over medium-high heat. Add the ground beef, cooking it while breaking up any large pieces with a spatula until it starts to brown and the fat is rendered, approximately 4 minutes.
Stir in chopped onion and continue to cook, stirring frequently until the onion is translucent and the beef is evenly crumbly, about 4 more minutes. If you prefer, drain any excess fat at this stage.
Sprinkle in your favorite taco seasoning and let it cook for an additional minute to release the flavors.
Mix in tomato paste along with a splash of water, using a spoon to scrape up any flavorful browned bits from the bottom of the pan. Stir everything until it's well blended.
Lower the heat to medium-low and let the mixture simmer until it thickens, around 5 minutes.
