Preheat the oven to 425° and line 2 rimmed baking sheet with parchment paper.
Place ground beef, breadcrumbs, milk, eggs, parsley, salt, pepper, and garlic powder in a large bowl. I like to use the bowl of a stand mixer and combine with the paddle attachment. If you don’t have one, your hands are your best tool for mixing the meat.
Using a 1 tablespoon size cookie scoop, scoop the meat mixture, one scoop at a time, into your hands, roll it into the shape of a ball, place on the baking sheet.
Continue until all the meatballs are made.
Bake for 10-12 minutes, or until the internal temperature is 160°.
While the meatballs are baking, add all the sauce ingredients to a small bowl or measuring cup and whisk to combine well.
Add the cooked meatballs to the Crockpot, pour the sauce on top, and gently stir so the meatballs are coated in the sauce.
Cook on low for 2 hours.