In a medium bowl, combine the breadcrumbs, nutmeg, allspice, garlic powder, and salt. (Note: Mixing the dry ingredients first will ensure the seasoning is evenly distributed throughout the meatballs and prevent you from overworking the meat mixture.)
Meanwhile, add the pork and beef to a large bowl. Lightly whisk the egg, then add it to the bowl with the meat. Lastly, add the breadcrumb mixture.
Use your hands to mix the meat and seasonings together until evenly combined, but avoid overmixing.
Divide and shape the meat mixture into 16 meatballs, about 1.5 Tbsp each.
Add 1 Tbsp of the butter to a large skillet and heat over medium. When the butter is melted and foaming, add the meatballs. Cook for a minute or two on each side, or until well browned. The meatballs do not need to be cooked through at this point.
Remove the browned meatballs from the skillet. Add the remaining 3 Tbsp butter and the flour. Whisk the butter and flour together as the butter melts. Cook the butter and flour mixture for about two minutes.
Slowly whisk in the beef broth, making sure to release all of the browned bits off the bottom of the skillet. Allow the broth to come up to a simmer, at which point it will thicken.
Stir in the Worcestershire sauce, pepper, nutmeg, and heavy cream. Taste the gravy and adjust the salt or seasonings to your liking.
Return the meatballs to the skillet and stir to coat in the sauce. Heat the meatballs over low, stirring occasionally, until heated through (about 5 minutes).
Serve the meatballs over mashed potatoes or egg noodles with a little chopped fresh parsley and cracked pepper for garnish.
NOTES
*We use Better Than Bouillon to make our broth. If using a low-sodium broth you may need to add more salt to the gravy for taste.