Brown ground beef over medium-high heat in a nonstick pot or pan until no longer pink.
Drain fat.
Add onions, tomato paste, taco seasoning, salt, pepper, water and mix until combined.
Reduce heat to Low and cook uncovered until beef is tender and excess liquid is reduced and meat mixture is thickened to your desired consistency.
Spoon mixture in taco shells and add toppings of your choice.
Serve immediately and enjoy!
Notes
Read all my tips above.
Leftover meat can be stored in the fridge for up to 3 days and reheated in the microwave. Don't store prepared tacos in fridge because the hard shells will become soggy.