Cook egg noodles according to package directions until al dente. Drain, toss with a small amount of butter to prevent sticking, and set aside.

Season chicken pieces generously with salt, pepper, and half the paprika. Heat 1 tablespoon butter and olive oil in a large skillet over medium-high heat. Add chicken in a single layer and cook for 3-4 minutes per side until golden and cooked through. Remove to a plate and set aside.

Add another tablespoon of butter to the same skillet. Add sliced mushrooms in an even layer and cook without stirring for 2-3 minutes to allow browning, then stir and continue cooking another 3-4 minutes until golden. Remove mushrooms to the plate with chicken.

Add remaining tablespoon of butter to the skillet. Sauté diced onion for 3-4 minutes until softened. Add minced garlic and cook for 30 seconds until fragrant, stirring constantly.

Sprinkle flour over the onions and garlic, stirring constantly for 1 minute to cook out the raw flour taste.

Slowly pour in chicken broth while whisking continuously to prevent lumps. Add remaining paprika, Dijon mustard, and dried thyme. Bring to a gentle simmer and cook for 2-3 minutes until sauce thickens.

Reduce heat to low. Return cooked chicken and mushrooms to the skillet along with any accumulated juices. Stir to coat in sauce and warm through for 2 minutes.

Remove skillet from heat completely. Stir sour cream and heavy cream together, then gradually add to the skillet, stirring constantly. Taste and adjust seasoning with salt and pepper as needed.

Serve immediately over prepared egg noodles and garnish generously with fresh chopped parsley.