Saucy sweet and sour meatballs with red peppers and pineapple made right in your crockpot!
In a large bowl combine ground beef, egg and yolk, breadcrumbs, salt, pepper, garlic powder, and onion powder. Use your hands to mash everything together until the ingredients are well-mixed. Roll the mixture into 1.5 inch balls. Place meatballs side by side in a single layer in the bottom of a greased crockpot. Add pineapple chunks (without juice) and red peppers.
Prepare the sauce by whisking together sugar, apple cider vinegar, soy sauce, garlic powder, onion powder, ketchup, and red pepper flakes in a bowl. Pour over meatballs in the crockpot. Cover and cook on high for 1-2 hours or on low 3-4 hours.
About 30 minutes before serving, in a small bowl whisk together cold water and corn starch. Pour into crockpot and stir. Cover and allow to thicken for about 30 minutes before serving. Sprinkle with sesame seeds if desired.
Alternate oven cooking method: instead of placing meatballs in the slow cooker, place them on a greased baking sheet along with the chopped red peppers. Bake them for 15-20 minutes until cooked though and browned. Remove from oven and add to a large sauce pan with your sweet and sour sauce, the cooked red peppers, and the pineapple chunks and stir over medium heat. Add the corn starch slurry and allow to thicken for about 5 minutes before serving.