1. 1. Prepare the slow cooker: Lightly grease the inside of your slow cooker crock with cooking spray or line it with a slow cooker liner for easy cleanup. This prevents the sauce from sticking and burning.

2. 2. Whisk the sauce ingredients: In a medium bowl, combine the ketchup, honey, soy sauce, apple cider vinegar, minced garlic, ground ginger, and red pepper flakes (if using). Whisk until all the ingredients are well combined and the honey is fully incorporated into the sauce. The mixture should be smooth and uniform in color.

3. 3. Add meatballs and sauce: Carefully place the frozen meatballs into the prepared slow cooker. Pour the whisked honey garlic sauce evenly over the meatballs, making sure to coat them thoroughly. Gently stir to ensure all the meatballs are submerged or covered in the sauce.

4. 4. Cook the meatballs: Cover the slow cooker with its lid. Cook on the “LOW” setting for 4-6 hours, or on the “HIGH” setting for 2-4 hours. The meatballs are done when they are heated through to an internal temperature of 165 F (74 C) and the sauce is bubbly and slightly thickened.

5. 5. Thicken the sauce (optional): If you prefer a thicker sauce, create a cornstarch slurry. In a small bowl, whisk together the 2 tablespoons of cornstarch with 2 tablespoons of cold water until smooth. Stir the slurry into the slow cooker during the last 30 minutes of cooking. Continue to cook until the sauce has reached your desired consistency, stirring occasionally.

6. 6. Serve and enjoy: Once cooked, give the meatballs a final stir. They are now ready to be served hot. The sauce will be glossy and clinging to the meatballs, indicating they are perfectly coated and delicious.