Sweet Potato Bun Sliders & Fries

Name: Sweet Potato Bun Sliders & Fries
Prep time: 25 min
Cook time: 45 min
Total time: 1 h 10 min
Cuisine: American
Ingredients: 3 large sweet potatoes (1 ½ pounds), about 2 inches thick in the middle; 3 tablespoons extra virgin olive oil; 1 teaspoon kosher salt; ½ teaspoon ground pepper; 1 pound ground beef (85% lean); 1 large egg; 1 small onion, grated; 1 tablespoon yellow mustard; 1 tablespoon soy sauce; 1 teaspoon kosher salt; ½ teaspoon black pepper; Garnish: Green leaf lettuce