1 Tbsp cornstarch
1 (32 oz) carton low-sodium beef broth, divided (4 cups)
2 1/2 Tbsp olive oil, divided
12 oz. baby bella (cremini) mushrooms, cleaned, sliced 1/4 inch thick
1 cup chopped yellow onion
3 garlic cloves, minced (1 Tbsp)
1 lb lean ground beef
Salt and freshly ground black pepper
1 tsp paprika
1 Tbsp dijon mustard
2 tsp Worcestershire
8 oz. dry egg noodles* (5 cups)
3/4 cup sour cream,** rested at room temperature while everything cooks
2 Tbsp minced fresh parsley
In a small bowl whisk cornstarch with 2 Tbsp of the beef broth, set aside.
Heat 2 Tbsp olive oil in a 12-inch saute pan with tall sides or pot over medium-high heat.
Add mushrooms and onions and saute, tossing only occasionally (about every 3 minutes), until browned, about 10 - 12 minutes.
Add garlic and saute 1 minute longer. Transfer mixture to a sheet of foil or plate.
Heat remaining 1/2 Tbsp oil in pan over medium-high heat. Break beef into 6 portions and add to skillet, season lightly with salt and pepper.
Let brown on bottom, about 3 minutes then turn and start breaking up beef, and let continue to cook until just nearly cooked through, about 3 minutes longer.
Drain fat if needed (if you used 90% lean you shouldn't need to) then add paprika and cook 30 seconds longer.
Pour in remaining beef beef broth while scraping up browned bits from the bottom of pan. Add in dijon mustard, Worcestershire, mushroom mixture and season with salt and pepper to taste.
Bring mixture to a simmer, add egg noodles and toss mixture, cover and reduce heat to medium-low and let simmer 3 minutes.
Whisk cornstarch mixture once more then pour into liquid in pan, toss mixture then cover and continue to cook until noodles are al dente, about 2 - 3 minutes longer.
Finish with sour cream and garnish: Remove from heat, add in sour cream and toss. Let sit for 1 minute.
Sprinkle with parsley and serve warm.