Preheat the oven to 400°F (200°C).
In a small bowl soak the ½ cup panko breadcrumbs in the ½ cup milk. The breadcrumbs will absorb the milk and become soggy.
In a food processor pulse the ½ cup parmesan cheese, ½ cup fresh parsley, 1 large onion , and 3 cloves of garlic until finely chopped.
Add the breadcrumb/milk mixture, onion mixture, 1 pound of ground beef, 1 pound of ground mild Italian sausage, 2 large eggs, 1 teaspoon kosher salt, 1 teaspoon black pepper, 1 teaspoon Worcestershire sauce, ½ teaspoon dried basil, and ½ teaspoon dried oregano to a large bowl. Mix with your hands until just combined.
Shape the mixture into one-inch meatballs using approximately 2 tablespoons of the mixture for each meatball. When shaping the meatballs keep them loose. Rolling and squeezing them into tight balls will create tough overworked meatballs. Place the meatballs on a foil-lined baking sheet.
Bake for 18-20 minutes. Meatballs are done when they reach an internal temperature of 165°F (74°C). You can also cut a meatball in half to make sure the meat is no longer pink.