Made this for my mom and she thought we went to a fancy restaurant. The most luxurious Sunday dinner with barely any effort

Directions

Pat the beef tenderloin dry with paper towels and let it sit at room temperature for about 20–30 minutes while you set up the slow cooker. This takes the chill off the meat so it cooks more evenly and stays a consistent pink from edge to center.

Place the whole beef tenderloin in the bottom of a 5- to 6-quart slow cooker, curving it slightly if needed so it fits in a single layer without overlapping.

Pour the champagne evenly over the tenderloin, lifting it slightly with a fork or tongs so some of the liquid runs underneath. The meat does not need to be fully submerged; you’re aiming for it to sit in a shallow bath of champagne.

Dot the top of the tenderloin with the pieces of salted butter, spacing them out so they melt and baste the meat as it cooks. Cover the slow cooker with the lid, making sure it’s seated well so steam doesn’t escape.

Cook on LOW for 1 1/2 to 2 1/2 hours, depending on the thickness of your tenderloin and your slow cooker’s heat level, until the internal temperature reaches about 130°F for medium-rare or 135°F for medium when checked with an instant-read thermometer inserted into the thickest part.

Begin checking around the 1 1/4-hour mark; tenderloin cooks more quickly than tougher cuts, and you want to avoid overcooking.

Once the tenderloin reaches your preferred doneness, carefully transfer it from the slow cooker to a cutting board, tent it loosely with foil, and let it rest for 15–20 minutes. Resting allows the juices to redistribute and helps keep the slices perfectly pink and moist.

While the meat rests, make the champagne reduction sauce right in the slow cooker. Turn the slow cooker to HIGH and remove the lid. Let the cooking liquid simmer with the lid off for 15–25 minutes, stirring occasionally, until it reduces by roughly half and turns into a pale golden, slightly thickened sauce with a glossy, silky finish.

Small bubbles across the surface are what you want; if your slow cooker doesn’t simmer strongly on HIGH, you can pour the liquid into a saucepan and reduce it over medium heat on the stovetop instead.