In your crockpot, combine the ketchup, grape jelly, Worcestershire sauce, and garlic powder. Stir vigorously until the jelly is fully dissolved and the mixture is smooth and uniform—this ensures even flavor distribution throughout the dish. I like to take a moment here to taste the sauce and adjust the Worcestershire if needed; a little extra adds nice depth without overpowering the grape jelly's sweetness.

Add the frozen pre-cooked meatballs directly to the sauce mixture and stir gently to coat them evenly. Cover the crockpot and cook on low for 3-4 hours, or on high for 1-2 hours, until the sauce is bubbling gently around the edges and the meatballs are heated through. (Alternatively, you can transfer everything to a stovetop pot and simmer over medium-low heat for 15-20 minutes until heated through.) The longer cooking time on low allows the flavors to meld beautifully without scorching the sauce.

Transfer the meatballs and sauce to a serving dish or keep them warm in the crockpot on the warm setting if serving buffet-style. Garnish with freshly chopped parsley for a pop of color and freshness—it provides a nice contrast to the rich, sweet sauce and makes the dish feel more intentional.