Ingredients:

  • 3 lbs beef chuck roast, cut into 1-inch cubes
  • 2 tbsp vegetable oil
  • 1 tsp salt
  • 1/2 tsp black pepper
  • 1 lb baby bella mushrooms, sliced
  • 1 large onion, finely diced
  • 4 cloves garlic, minced
  • 2 cups low-sodium beef broth
  • 2 tbsp Worcestershire sauce
  • 1 tbsp Dijon mustard
  • 8 oz full-fat sour cream, room temperature
  • 2 tbsp cornstarch
  • 2 tbsp cold water
  • 2 tbsp cold butter, cubed

Instructions:

  1. Heat vegetable oil in a skillet over high heat until just smoking. Pat the beef dry and season with salt and pepper. Sear the meat in batches until a deep, mahogany-colored crust forms on all sides, then transfer the browned beef to the slow cooker.
  2. Add the sliced mushrooms, diced onion, and minced garlic directly on top of the meat in the slow cooker. Pour in the beef broth, Worcestershire sauce, and Dijon mustard, stirring gently to combine the liquid.
  3. Cover and cook on Low for 8 hours or High for 4-5 hours until the meat yields easily to a fork.
  4. Stir in the cornstarch and water slurry and cook on high for an additional 15 minutes until the sauce thickens.
  5. Turn off the heat; swirl in the cold butter and room-temperature sour cream until the sauce is velvety and uniform.