In a large mixing bowl, stir together the breadcrumbs and milk. Let sit for 3–5 minutes until the mixture softens into a paste (panade).
3/4 cup plain breadcrumbs, 1/2 cup milk
Add the egg, minced onion, garlic, salt, pepper, and dried Italian seasoning or parsley to the bowl. Stir until everything is well combined.
1 large egg, 1/4 cup onion, 2 cloves garlic, 1 teaspoon kosher salt, 1/2 teaspoon black pepper, 1/2 teaspoon dried Italian seasoning
Add the ground beef and ground pork to the bowl. Using clean hands, gently mix just until evenly combined, being careful not to overwork the meat.
1 1/2 pounds ground beef, 1/2 pound ground pork
Using a tablespoon or small cookie scoop, form 1–1 1/4 inch meatballs and place them on a lined baking sheet or large plate. You should get about 40–45 small meatballs. Lightly wet your hands with cold water if the mixture is sticky.
Heat the neutral oil in a large skillet over medium-high heat. Add the meatballs in a single layer without crowding and brown for 2–3 minutes per side, just until they develop a golden crust. Transfer browned meatballs to the slow cooker, working in batches as needed. (You can skip browning and add raw meatballs directly to the slow cooker, but browning adds flavor and helps them hold their shape.)
1-2 tablespoons neutral oil
In a medium bowl, whisk together the cranberry sauce, ketchup, brown sugar, apple cider vinegar, Worcestershire sauce, smoked paprika, and red pepper flakes (if using) until smooth. Taste and adjust with a pinch of salt and pepper if needed.
1 can whole berry cranberry sauce, 1 cup ketchup, 1/2 cup brown sugar, 2 tablespoons apple cider vinegar, 1 tablespoon Worcestershire sauce, 1/2 teaspoon smoked paprika, 1/4 teaspoon crushed red pepper flakes, Salt and pepper
Pour the cranberry sauce mixture over the meatballs in the slow cooker. Gently stir or shake the cooker so all the meatballs are coated. Cover with the lid.
Cook on LOW for 3–4 hours or on HIGH for 1 1/2–2 hours, until the meatballs are cooked through and the sauce is bubbling and thick enough to coat a spoon. Stir once or twice during cooking so the meatballs cook evenly and do not stick. Meatballs are done when firm but tender and reach an internal temperature of 165°F (74°C).
Once cooked, switch the slow cooker to WARM. Serve the meatballs straight from the crockpot with toothpicks or a small ladle, stirring occasionally so the top layer doesn’t dry out.
To use frozen pre-cooked meatballs, place 40–50 frozen meatballs directly into the slow cooker, pour the prepared cranberry sauce mixture over them, and cook on LOW for 3–4 hours until heated through and well coated.
40-50 frozen plain meatballs