Preheat the oven to 400°F. Line a baking sheet with foil and spray with non-stick spray.
Combine the meat, egg, breadcrumbs, cheese, salt, garlic powder, onion powder, black pepper and parsley in a bowl. Stir just until combined, do not over mix. Add a Tablespoon or two of water as needed to keep a wet mixture.
Use a medium cookie scoop or spoon to scoop the meat. Then form into 1 1/2" balls and place on the pan.
Bake uncovered for 17-18 minutes, or until no longer pink in the middle. Turn halfway through, so the bottoms don't brown.
While the meatballs are cooking, make the roux. Melt the butter in a skillet over medium heat. Once it starts bubbling, slowly whisk in the flour. Cook for 3 minutes, or until is has turned a caramel color. Add the Worcestershire sauce and then slowly whisk in the broth. Whisk until smooth. Add more flour if needed to thicken, or more broth if you need to thin the sauce.
Remove from heat and mix in the sour cream. Salt and pepper to taste.
Once the meatballs are done, add them to the sauce and let simmer an additional minute. Serve over egg noodles or mashed potatoes. Top with fresh parsley if desired.
Cooking meatballs on skillet: You can also cook the meatballs in a pan with 2 Tablespoons oil over medium-high heat for 7-10 minutes, or until cooked through.Substitutions: You can use 1/2 teaspoon garlic powder and onion powder if you do not have fresh garlic and onions.For juicier meatballs: If I have pork on hand, I like to use 1/2 pound ground beef and half pound ground pork.