Place ground beef, ground turkey, eggs, breadcrumbs, onion, Italian seasoning, garlic powder, salt, and pepper into a large bowl; gently mix together with your hands or a metal spoon to combine, careful not to over-mix.
Using a cookie scoop or your hands, divide the meat mixture into desired size meatballs.
Place meatballs in a zip bag and freeze them.
To Make Slow Cooker Grape Jelly Meatballs
Place the frozen meatballs in the Crock Pot. Pour the grape jelly, BBQ sauce, ketchup, sriracha, salt and chili flakes over the meatballs.
Mix the meatballs in the sauce until they are all evenly coated.
Cover the Crock Pot with lid and cook on HIGH temperature for 3 to 3½ hours.
Remove lid and garnish with fresh chopped parsley.
Turn the slow cooker's dial to the "warm" setting, and keep on the "warm" setting while serving.
Notes
Meatballs: I made these meatballs using ground beef and ground turkey. However, you can make them with only ground beef, only ground turkey, or ground chicken. Store-bought frozen meatballs are also a great option.
Jelly: Grape Jelly is the traditional choice, but you can use other jellies like apricot or strawberry.
Oven + Stovetop Method: Bake the meatballs at 400˚F for about 15 minutes or until cooked through. Then, place the meatballs in a large Dutch oven, mix in the sauce ingredients, and simmer over medium heat for about 10 minutes or until hot.
Sriracha Sauce: You can use Sriracha, or you can use your favorite hot chili sauce. If you do not like spicy foods, you can leave it out altogether.