Sauté the Aromatics
Heat butter and olive oil in a skillet over medium heat. Add onion and cook for 2–3 minutes until soft. Stir in garlic and cook for 30 seconds more.
Cook the Mushrooms
Add sliced mushrooms and sauté for 6–8 minutes until browned and most of the moisture evaporates.
Deglaze with Wine
Pour in the white wine (or broth), scraping up any bits from the bottom of the pan. Let simmer for 2–3 minutes to reduce slightly.
Add Cream and Simmer
Stir in the heavy cream and Worcestershire (if using). Let the sauce simmer gently for 3–5 minutes until slightly thickened.
Season and Serve
Season with salt and black pepper to taste. Garnish with fresh herbs and spoon over cooked steak immediately.