Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper.
Step 2: In a large bowl, combine the ground beef, breadcrumbs, egg, chopped onion, minced garlic, Worcestershire sauce, salt, and pepper. Mix gently with your hands until just combined, being careful not to overmix.
Step 3: Roll the mixture into 1-inch meatballs and place them on the prepared baking sheet. Bake for 18-20 minutes, or until cooked through and lightly browned.
Step 4: While the meatballs are baking, prepare the cranberry sauce. In a medium saucepan, combine the cranberries, orange juice, brown sugar, apple cider vinegar, Dijon mustard, and ground ginger (if using).
Step 5: Bring the mixture to a simmer over medium heat, stirring occasionally. Reduce heat to low and cook for 10-15 minutes, or until the cranberries have burst and the sauce has thickened. You can gently mash some of the cranberries with a spoon for a smoother sauce if desired.
Step 6: Once the meatballs are cooked, add them directly to the cranberry sauce in the saucepan. Stir gently to coat all the meatballs evenly.
Step 7: Simmer the meatballs in the sauce for another 5-10 minutes, allowing the flavors to meld. Serve warm, garnished with fresh rosemary sprigs and orange zest if desired. These are excellent served directly from a slow cooker on the 'warm' setting for parties.