Preheat your oven to 350 F. Spray baking sheet(s) with non-stick spray
Combine the ingredients. In a large mixing bowl, combine the ground beef, ground pork, panko, onion, garlic, eggs, milk, parsley, allspice, nutmeg, salt, and pepper. Use your hands to gently mix the ingredients until evenly combined, being careful not to over-mix
Form the meatballs. Roll the mixture into balls about 1 to 1 ½ ounces each. If you have a kitchen scale you can weigh them. If not, aim for meatballs about the size of a golf ball
Bake the meatballs in the oven until cooked through (about 10 to 12 minutes)
Make the sauce. Melt the butter in a skillet over medium heat. Whisk in the flour until combined and cook for about 1 minute. Slowly add the beef broth, stirring continuously. Bring to a simmer and then stir in the heavy cream, Dijon, Worcestershire, and Better than Bouillon
Add the cooked meatballs to the skillet and spoon the sauce on top. Let simmer for about 5 minutes
Serve. Garnish with fresh parsley and serve over mashed potatoes, egg noodles, or rice