Step 1: Cook the Beef Filling

1. Heat a large skillet over medium heat. If your ground beef is very lean, add 1 tablespoon of olive oil to the pan.
2. Add the ground beef and cook, breaking it up with a spatula, until browned, about 5–7 minutes. Drain any excess grease.
3. Stir in the chopped onion and garlic. Cook for another 3–4 minutes, until the onion is softened and fragrant.
4. Add the taco seasoning, tomato sauce, and water. Stir to coat the beef evenly in the sauce. Let the mixture simmer for 5 minutes, or until slightly thickened. Remove from heat and set aside.

Step 2: Warm the Tortillas

1. Wrap the tortillas in aluminum foil and warm them in a 350°F (175°C) oven for 5–7 minutes. Alternatively, heat each tortilla in a dry skillet over medium heat for 20–30 seconds per side.

Step 3: Assemble the Burritos

1. Lay a warm tortilla on a clean surface.
2. Spread a spoonful of sour cream in the center of the tortilla.
3. Layer 1/6th of the cooked rice, black beans, and seasoned beef on top. Sprinkle with shredded cheese, salsa, and any additional toppings of your choice.
4. Fold in the sides of the tortilla, then roll it up tightly from the bottom to form a burrito.

Step 4: Serve or Toast

1. Serve the burritos as is, or toast them for a crispy finish. To toast, place each burrito seam-side down in a skillet over medium heat. Cook for 1–2 minutes on each side, or until golden and slightly crispy.
2. Slice the burritos in half and serve with extra salsa, guacamole, or hot sauce on the side.