In a large mixing bowl, combine beef, pork, diced onions, minced garlic, egg, panko, milk, salt, and pepper.
Once all ingredients are combined, form 1 inch meatballs.
Heat frying pan to medium heat with just enough oil to cover bottom of the pan.
Place meatballs in hot skillet and sear on all sides. Move the cooked meatballs to a plate and continue to work in batches.
Once all the meatballs are done cooking and resting on a covered plate, add butter to skillet.
When butter is melted, stir in flour and cook for about 2 minutes.
Add beef broth, worcestershire sauce, and dijon to the skillet and continue to stir.
Add heavy cream to skillet and simmer until the sauce thickens.
Put meatballs back into the skillet and simmer for 10 minutes, stirring and spooning the sauce to cover the meatballs.
Serve immediately.