Combine ground beef, bread crumbs, pepper, egg, salt, soy sauce, and milk in a bowl.

Mix the ingredients thoroughly until well combined.

Cover the mixture and refrigerate for 1 hour to allow the flavors to meld.

Shape the meat mixture into walnut-sized balls.

Heat salad oil in a skillet over medium heat.

Cook the meatballs slowly in the skillet until they are browned and cooked through.

Remove the meatballs from the skillet and drain off any excess fat.

In the same skillet, blend flour and oil together.

Cook the flour and oil mixture, stirring constantly, until it comes to a boil.

Continue stirring until the sauce is smooth and bubbly.

Reduce the heat to low and simmer for 1 minute.

Add sour cream to the sauce and stir until well combined.

Return the meatballs to the skillet and coat them with the sauce.

Serve hot.