In a 2-4 quart slow cooker, combine cranberry sauce, honey, vinegar, broth, corn starch, garlic, salt and pepper flakes with a whisk until relatively smooth.
Stir in the meatballs.
Cover and cook on low for 4-6 hours or high for 2-3 hours, until meatballs are heated through and sauce has thickened.
Serve alone as an appetizer or over rice or mashed potatoes.
1 lb of meatballs will leave a good amount of sauce for spooning over rice or mashed potatoes. If you're serving this as an appetizer and don't need the extra sauce, add up to 1.5-2 lbs of meatballs to serve more people.