Creating this delicious Creamy Mushroom Sauce for Steak Lovers is simple and straightforward. Follow these steps:

1. Heat the Pan: In a large skillet, heat the olive oil and butter over medium heat until the butter melts and begins to bubble.
2. Sauté the Mushrooms: Add the sliced mushrooms to the skillet. Sauté for about 5-7 minutes, stirring occasionally until the mushrooms are golden brown and have released their moisture.
3. Add Garlic: Stir in the minced garlic and cook for an additional 1-2 minutes until fragrant. Be careful not to burn the garlic.
4. Combine liquids: Pour in the heavy cream, beef broth, Worcestershire sauce, and Dijon mustard. Stir well to combine all ingredients.
5. Simmer: Bring the mixture to a gentle simmer. Let it cook for about 5-10 minutes, stirring occasionally, until the sauce thickens slightly.
6. Season: Taste and adjust seasoning with salt and pepper as necessary. If you desire a richer sauce, sprinkle in the grated Parmesan cheese and stir until melted and combined.
7. Finish and Garnish: Once the sauce reaches your desired consistency, remove it from the heat. Stir in the chopped parsley for a fresh touch and added color.
8. Serve Immediately: Pour the sauce over your cooked steak or serve it on the side for dipping.

With these simple steps, you can master the art of making this heavenly sauce in no time!