STEP 1: PREHEAT THE OVEN AND SEASON THE BEEF

Start by preheating your oven to 400°F (200°C). This high heat will give the beef a beautifully caramelized exterior while keeping the interior juicy and tender. While the oven is heating up, season the beef tenderloin roast generously with salt, pepper, and chopped fresh rosemary. Rub the minced garlic into the surface of the beef, ensuring that the flavors penetrate the meat. Let the beef sit at room temperature for about 15 minutes before cooking to ensure even cooking throughout.

STEP 2: SEAR THE BEEF

Heat the olive oil in a large oven-safe skillet over medium-high heat. Once the oil is hot, place the beef tenderloin in the pan and sear it on all sides for about 2-3 minutes per side, or until a deep brown crust forms. This step adds flavor and helps lock in the juices. Once the beef is nicely seared, remove it from the pan and set it aside.

STEP 3: ROAST THE BEEF

Return the beef to the skillet and place it in the preheated oven. Roast the tenderloin for about 25-30 minutes for medium-rare, or 30-35 minutes for medium. The internal temperature should reach 130°F (54°C) for medium-rare or 140°F (60°C) for medium. Use a meat thermometer to check the internal temperature, as this will ensure the beef is cooked to your desired level of doneness.

While the beef is roasting, you can prepare the mushroom sauce.

STEP 4: MAKE THE MUSHROOM SAUCE

While the beef is roasting, heat the butter in a large saucepan over medium heat. Add the chopped onion and cook for 3-4 minutes until softened and translucent. Add the minced garlic and cook for another 30 seconds until fragrant.

Next, add the sliced mushrooms and cook for about 7-8 minutes, stirring occasionally, until the mushrooms are browned and softened. This is where the mushrooms will release their moisture and start to caramelize, creating deep flavor.

Once the mushrooms are cooked, add the beef broth to the pan. Use a wooden spoon to scrape up any browned bits from the bottom of the pan, which will add richness to the sauce. Let the broth simmer for about 3-4 minutes to reduce slightly. Then, stir in the heavy cream and chopped rosemary. Continue to cook the sauce for another 3-4 minutes, or until it thickens to your desired consistency. Season with salt and pepper to taste.

STEP 5: REST THE BEEF

Once the beef has reached the desired temperature, remove it from the oven and let it rest for 10-15 minutes. This allows the juices to redistribute and keeps the beef tender and juicy. While the beef is resting, finish the mushroom sauce.

STEP 6: SERVE

After the beef has rested, slice it into 1-inch thick slices. Arrange the slices on a serving platter and spoon the mushroom sauce generously over the top. Garnish with fresh parsley for a burst of color and flavor.