Peel and chop sweet potatoes into even pieces. Place in a large pot of salted water, bring to a boil and cook until tender, about 15-20 minutes. Drain and mash with butter, cream, salt, and pepper until smooth.

In a mixing bowl, combine ground pork, panko breadcrumbs, grated apple, chopped sage, grated garlic, salt, pepper, allspice, and egg. Mix gently until just combined, shape into 1.5-inch meatballs.

Preheat oven to 400°F (200°C). Arrange meatballs on a parchment-lined baking sheet, broil for 2-3 minutes for a crispy exterior, then bake for 20-25 minutes or until cooked through and internal temperature reaches 160°F (71°C).

On serving plates, spoon a generous portion of creamy sweet potatoes and top with freshly baked meatballs. Garnish with additional sage leaves if desired.