Heat the oven to 400°F. Scrub the sweet potatoes, pat them dry, and prick each one several times with a fork. Place them on a baking sheet and bake until tender when pierced with a knife, about 45 to 55 minutes.

While the potatoes bake, combine the ground turkey, ground beef, panko, egg, diced onion, garlic powder, smoked paprika, salt, black pepper, and 3 tablespoons of the BBQ sauce in a mixing bowl. Mix gently until just combined.

Shape the meat mixture into four compact oval loaves and place them on a separate baking sheet. Bake until cooked through, about 20 to 25 minutes. Brush the tops with 1 tablespoon of the remaining BBQ sauce during the last 5 minutes of baking.

Let the sweet potatoes cool just enough to handle. Cut a lengthwise slit in each one and gently press the ends to open it. Fluff the inside with a fork.

Divide the meatloaves among the sweet potatoes. Drizzle with the remaining BBQ sauce, then sprinkle with cheddar cheese. Return the potatoes to the oven for 3 to 5 minutes, until the cheese melts.

Finish with sliced green onions and serve warm.