Prepare the Potatoes:

1. Preheat your oven to 400°F (200°C).
2. Scrub the Russet potatoes clean and poke each one several times with a fork.
3. Place the potatoes directly on the oven rack or on a baking sheet, and bake for 45-60 minutes, until they are tender when pierced with a fork.

Cook the Ground Beef:

1. Add the lean ground beef and cook until browned, breaking it up as it cooks.
2. Drain any excess grease, then stir in the taco seasoning according to the package instructions (typically with a bit of water).
3. Let it simmer for a few minutes until the seasoning is well incorporated and the sauce thickens.
4. Remove from heat and set aside.

Assemble the Taco Potatoes:

1. Once the potatoes are done baking, carefully cut each potato down the center and fluff the inside with a fork.
2. Top each potato with a generous portion of the seasoned ground beef.

Add Toppings:

1. Now comes the fun part! Add your favorite taco toppings such as shredded lettuce, cheddar cheese, sour cream, salsa, guacamole, and green onions.
2. Customize each potato to your liking and serve immediately.