Add your meatballs, cream of mushroom soup, beef broth, sliced mushrooms, Dijon mustard, Worcestershire sauce, and seasonings to your crockpot. Give everything a good stir and start cooking.
In a skillet over low-medium heat, melt 2 tbsp butter. Add your sliced onion and 1 tsp sugar. Cook for approximately 20 minutes, stirring occasionally, until the onions are soft, golden, and caramelized.
Add your caramelized onions to the crockpot and stir to combine. Cover and cook on HIGH for 2 hours or LOW for 4 hours, until everything is heated through and the meatballs are fully cooked.
Just before serving, boil 1 lb of egg noodles according to the package directions. Drain and set aside.
Stir 1 cup of full-fat sour cream into your crockpot until the sauce is smooth and creamy. Add your cooked egg noodles and gently toss everything together.
Top with fresh parsley and serve with warm garlic bread for the ultimate comfort meal!
