1. Heat oven to 350 F. Line two baking sheets with silicone baking sheets.
2. In a small bowl, stir together the stuffing and the stock. Let the mixture sit about 2 minutes to soften.
3. Place the turkey in a large mixing bowl. Add the salt, pepper, apple, poultry seasoning, eggs and stuffing mixture and stir until well blended. Form mixture into 1 1/2 inch balls and place on baking sheet. Bake until they're cooked thoroughly, firm, and golden, about 20 minutes.
4. While the meatballs bake, make the cranberry dip. In a medium saucepan over medium-high heat, stir together the cranberries, orange juice, and the sugar. Bring the mixture to a boil, then reduce the heat to low and simmer, stirring occasionally, until the mixture is slightly thickened. Remove the pan from the heat and stir in the mustard. Use an immersion blender to puree the sauce. Serve it on the side with the meatballs.