Beef Tenderloin with Creamy Mushroom Sauce

Preheat the oven to 240°C / 450°F.
Tuck the thin tail end of the tenderloin under itself and tie it with kitchen string at intervals to ensure an even shape for consistent cooking.
Pat the beef dry, rub all over with olive oil, salt, and pepper.
Roast the Beef:

Place the beef on a rack set over a roasting pan.
Roast the beef for:
25 minutes for rare
30 minutes for medium-rare
35 minutes for medium (see note for exact beef temperatures).
Remove from the oven and transfer the beef to a tray. Cover loosely with foil and rest for 20 minutes.
Make the Creamy Mushroom Sauce:

While the beef rests, melt the butter in a skillet over high heat.
Add the mushrooms and cook for about 5 minutes until golden brown.
Add the garlic and cook for 1 minute.
Pour in the wine or broth and stir, scraping up any brown bits from the skillet.
Add the beef broth, heavy cream, Dijon mustard, and thyme. Bring the mixture to a simmer and cook for about 5 minutes, until it thickens slightly. Adjust seasoning with salt and pepper.
Serve:

Slice the beef tenderloin into thick slices.
Serve with the creamy mushroom sauce on top and garnish with freshly chopped parsley or chives.
Serving and Storage Tips