I start by melting the butter in a skillet over medium-high heat. Once it's hot and melted, I add the sliced mushrooms and garlic, stirring gently. I let them cook for about 3–4 minutes, until the mushrooms brown nicely but still retain a firm, meaty texture.
Next, I pour in the chicken broth, then add the heavy cream, Dijon mustard, and Worcestershire sauce. I stir to combine everything, making sure the mustard and Worcestershire are fully distributed.
After combining, I lower the heat a little and let the sauce simmer for 5–8 minutes, stirring occasionally. During this time, the liquid reduces, and the sauce thickens into a rich, creamy consistency. I taste and adjust with salt and cracked pepper as needed.
Finally, I spoon the hot sauce generously over my cooked steak. For an extra touch, I sometimes add a bit more freshly cracked pepper. If I want a cheesier flavor, I’ll top with freshly grated Parmesan.