Preheat oven to 400°F. Line a rimmed baking sheet with aluminum foil.

Place the large baking potatoes onto the baking sheet, drizzle 1 tablespoon of olive oil over the potatoes, and gently rub the oil over the outer surface of the potatoes. Sprinkle 0.5 teaspoon of salt evenly over the surface of the oil-rubbed potatoes.

Bake the potatoes for 1 hour to 1 hour 15 minutes, or until the baked potatoes are fork tender when poked.

When the potatoes are nearing the end of their cooking time, you can make your taco filling by adding to a large skillet, on medium-high heat, the remaining 1 tablespoon olive oil, lean ground beef, diced yellow onion, salt, and black pepper. Cook and brown the ground beef for 5-6 minutes or until no pink remains. Drain off any excess fat from the skillet.

Add the taco seasoning and water to the skillet of cooked and drained ground beef. Stir to combine. Bring the mixture to a low boil, then reduce the heat and simmer for 3-5 minutes or until the sauce has thickened and most of the water has evaporated. Be sure to stir the mixture often to avoid burning the sauce. Remove the skillet of taco-seasoned ground beef from the heat and set it aside.

Once the potatoes are fully cooked, and fork-tender when pierced, remove the potatoes from the oven and cut a slit down the center of each potato with a sharp knife. Allow the baked potatoes to rest for 5 minutes before handling them. Once the potatoes are cool enough to handle, gently push on the ends of one potato until you get the center of the potato to pop open at the cut in the top of the potato.

With a small fork, gently fluffy or break up the inside of the baked potato, then scoop out 1-2 tablespoons of the baked potato to make space to add the taco fillings.

To fill the taco potatoes, evenly divide the taco-seasoned beef into the opening of each baked potato.

Once your potatoes are stuffed with the taco-seasoned ground beef, you can then add some shredded cheddar cheese, diced tomatoes, a dollop of prepared guacamole, a dollop of sour cream, and a sprinkle of chopped fresh cilantro or thinly sliced green onions. The toppings can be customized according to each person's preferences for serving.