Creating a classic beef stroganoff casserole is a straightforward process. Follow these step-by-step instructions to craft a dish that’s sure to impress:

Preparing the Beef and Noodles

1. Cook the Egg Noodles: In a large pot, bring salted water to a boil. Add the egg noodles and cook according to package instructions until al dente. Drain and set aside.
2. Brown the Beef: In a large skillet, heat olive oil over medium-high heat. Add the sliced beef and cook until browned on all sides. Remove the beef from the skillet and set aside.

Making the Creamy Mushroom Sauce

3. Sauté the Onions and Mushrooms: In the same skillet, add the chopped onions and sliced mushrooms. Cook until the onions are translucent and the mushrooms have softened.
4. Add Garlic: Stir in the minced garlic and sauté for another minute until fragrant.
5. Create the Roux: Sprinkle the flour over the mushroom mixture and stir well to combine. Cook for about 1 minute to remove the raw flour taste.
6. Add Broth and Simmer: Gradually pour in the beef broth while stirring continuously to prevent lumps. Allow the mixture to simmer until it thickens slightly.
7. Incorporate Sour Cream and Mustard: Lower the heat and stir in the sour cream and Dijon mustard. Mix until smooth and creamy. Season with salt and pepper to taste. For added depth, consider adding Worcestershire sauce and paprika.

Assembling the Casserole

8. Combine Ingredients: Preheat your oven to 350°F (175°C). In a large mixing bowl, combine the cooked noodles, browned beef, and creamy mushroom sauce. Mix until everything is evenly coated.
9. Transfer to Casserole Dish: Pour the mixture into a greased 9×13-inch casserole dish, spreading it evenly.
10. Bake: Place the casserole in the preheated oven and bake for 25-30 minutes, or until the top is slightly golden and bubbling.

Finishing Touches

11. Garnish and Serve: Remove the casserole from the oven and let it cool for a few minutes. Garnish with chopped fresh parsley before serving.