MAKE THE MEATBALLS: In a large skillet over medium heat, cook the onion in the oil for about 15 minutes, until fragrant and beginning to brown. Stir in the garlic and cook 1 minute more. Remove from heat.
Mix onion/garlic mixture together with the rest of the meatball ingredients. Mix well. I find it's easiest to use my hands, kind of squishing it all through my fingers, to thoroughly distribute everything.
Form into bite-size meatballs. I use a small cookie scoop to make them uniform size. Cook the meatballs in a large skillet over medium-high heat until nicely browned and a bit crusty, turning meatballs to brown on all sides. Remove from skillet and set aside.
COOK THE MUSHROOMS: Drain excess grease from the skillet, but leave any brown bits from frying the meatballs in the skillet. Add the butter and mushrooms and cook over medium-high heat until browned. Add seasonings to taste and the white (bottom) part of the sliced green onions. (The green onion tops will be added later.)
MAKE THE SAUCE: Stir the cornstarch into the beef broth. Pour over the mushrooms and bring to a boil stirring until thickened, about 2 minutes. Reduce heat to medium-low. Stir in the sour cream and blue cheese. Stir until everything is well combined. Add the cooked meatballs, cover and simmer for 15-20 minutes to combine flavors.
Add the cooked, drained egg noodles and gently stir everything together so the noodles get nicely coated with the sauce. Add the green onion tops. It's ready to serve!
Enjoy!
