Step 1: Prepare the Chicken
Start by seasoning the chicken breasts with salt and pepper. Slice the chicken into thin strips or bite-sized pieces to ensure even cooking.

Step 2: Cook the Chicken
In a large skillet, heat the olive oil and butter over medium-high heat. Add the chicken strips and cook them for about 5-6 minutes, or until they are browned and cooked through. Once done, remove the chicken from the skillet and set it aside.

Step 3: Sauté the Aromatics
In the same skillet, add the chopped onion and minced garlic. Sauté them for 2-3 minutes until softened and fragrant. This step adds a delicious base of flavor to the dish.

Step 4: Cook the Mushrooms
Add the sliced mushrooms to the skillet and cook for about 5 minutes, stirring occasionally, until they turn golden brown and release their juices.

Step 5: Thicken the Sauce
Sprinkle the flour over the mushrooms, stirring well to coat them evenly. This will help thicken the stroganoff sauce. Gradually pour in the chicken broth, stirring continuously to avoid lumps. The sauce will begin to thicken as it heats up.

Step 6: Add the Flavor Enhancers
Stir in the Worcestershire sauce and Dijon mustard, bringing a deep savory flavor to the dish. Allow the mixture to come to a simmer, ensuring all the ingredients are well combined.

Step 7: Add Creams and Simmer
Lower the heat to a gentle simmer and stir in the sour cream and heavy cream. Let the sauce cook for an additional 3-4 minutes, stirring occasionally, until it thickens and becomes creamy.

Step 8: Combine Chicken and Sauce
Return the cooked chicken strips to the skillet, stirring them into the creamy mushroom sauce. Cook for another 2-3 minutes, allowing the chicken to reheat and soak up the flavors of the sauce.

Step 9: Serve
Cook the egg noodles according to package instructions, then drain. Serve the creamy chicken and mushroom stroganoff over a bed of egg noodles. Garnish with fresh parsley for a touch of color and freshness, if desired.