Gently combine the ground beef and pork in a bowl using your fingers to break up any lumps.
1 pound Ground Beef, ½ pound ground pork
Add finely chopped onion, garlic, breadcrumbs, egg gently fold in to mix together.
1 onion, ¾ Cup bread crumbs, 1 Egg
Add milk and season well with salt and pepper.
5 Tablespoon Whole Milk, Salt and pepper
Shape mixture into small, round balls using a medium cookie scoop.
Place on a clean cookie sheet or a plate, cover and store in the fridge for 2 hours.
After 2 hours remove the meatballs from the refrigerator and in a cast-iron pan or heavy-bottom pan heat olive oil over medium heat.
Olive oil
When hot, gently add your meatballs and brown on all sides, in two or three batches depending on the size of your pan. I tested crowding a full batch into a 12 inch cast iron pan at once and the meatballs steamed instead of browning; working in batches keeps the pan hot enough for a real sear, and it's what gives the drippings you need for the one-pan sauce.
When browned, add to an ovenproof dish and cover. Place in a 350 oven and cook for 30 minutes.
OR if you are doing the one-pan method, leave the meatballs in the pan, cover with an oven safe lid and cook at 350 for 30 minutes.
How to make the sauce
In a heavy-bottomed frying pan, melt the butter over medium heat.( if not using the pan you cooked the meatballs in. If using the one-pan method, no butter is needed as the drippings from the meatballs will serve in place of the butter.Remove the cooked meatballs from the frying pan and place on a clean plate while you make the sauce in the pan you pulled from the oven. 3 Tablespoon Butter
Whisk in the flour and continue cooking, stirring continuously, for 2 minutes, allowing the flour to cook and bubble.
3 Tablespoon Flour, All Purpose
Add the vegetable stock and beef stock to the pan and continue to stir.
⅔ Cup vegetable stock, ⅔ Cup beef stock
Pour in the heavy cream, soy sauce and Dijon mustard, whisking to combine. Bring to a simmer and allow the sauce to thicken.
⅔ Cup Heavy Cream, 2 Teaspoons soy sauce, 1 Teaspoon dijon mustard
Continue to stir until the sauce reaches your desired consistency.
Add the cooked meatballs back into the creamy gravy and serve.