Prep the lettuce. Separate the leaves and pat them very dry. Dry leaves hold the fillings better and won’t get soggy.
Warm the pan. Heat a large skillet over medium-high.
Add oil if using lean meat.
Cook the aromatics. Sauté the onion for 2–3 minutes until softened. Add garlic and cook 30 seconds until fragrant.
Brown the meat. Add ground beef or turkey. Break it up with a spatula and cook until browned with little pink left, about 5–7 minutes.
Drain excess fat if needed.
Season deeply. Sprinkle in the taco seasoning. Stir to coat every bit. Add tomato paste and mix until the meat looks glossy.
Simmer for flavor. Pour in water or broth.
Lower heat and simmer 2–3 minutes until slightly thickened and saucy, not watery. Taste and adjust salt or heat.
Get toppings ready. Dice avocado, mince red onion, chop cilantro, and set out cheese, sour cream, and lime wedges.
Assemble. Lay out lettuce leaves. Spoon in a generous scoop of seasoned meat.
Top with cheese, avocado, pico, onion, and cilantro.
Finish and serve. Add a dollop of sour cream, a squeeze of lime, and any extras like jalapeños or hot sauce. Eat right away for the best crunch.