Bring a large pot of water to a boil and season generously with salt. Add the egg noodles and cook to al dente according to package instructions. Drain the noodles, return them to the pot, and toss with the butter. Cover and set aside. 

Heat a large non-stick skillet over medium-high heat. Add 1 tablespoon of the olive oil and the onion and lightly season with salt. Cook for 2 to 3 minutes until softened. 

Add the remaining 1 tablespoon of olive oil and the mushrooms and stir to combine. Cook for 8 to 10 minutes, leaving the vegetables undisturbed for 2 to 3 minutes at a time before stirring to allow the liquid to evaporate and the mushrooms to caramelize.

Stir in the garlic and thyme and cook for 1 minute until fragrant. Stir in the paprika and the Dijon mustard, coating the vegetables. Pour in the sherry, scraping up any browned bits from the bottom of the pan, and cook for about 1 minute or until the wine evaporates. 

In a small bowl, whisk together the Worcestershire sauce and cornstarch. Add the Worcestershire mixture, rotisserie chicken and chicken stock to the skillet.

Bring to a simmer and cook for about 5 minutes until the sauce has reduced and is slightly thickened.

Take the pan off the heat, remove the thyme sprigs and stir in the sour cream. Season with salt and black pepper. 

To serve, spoon the stroganoff over the noodles and garnish with chopped parsley. Enjoy! Leftovers can be stored in an airtight container in the refrigerator for up to 5 days.