Prep 20 mins
Cook 2 hrs
Entertain in elegance with this sumptuous beef roast and mouth-watering sauce.
- 4 lbs prime rib roast
- cream of mushroom soup mix, 1 packet
- 2 portabella mushrooms
- 1 cup beef stock
- 2 teaspoons flour
- 1 tablespoon balsamic vinegar or 1 tablespoon red wine vinegar
- Place roast, fat side up, on rack in roasting pan without lid.
- Rub mushroom soup mix over surface of roast.
- Insert meat thermometer into centre of roast, avoiding fat or bone.
- Roast at 325 degrees for 2 hours.
- Tent roast with foil and let stand for 10 to 15 minutes on cutting board before carving.
- Meanwhile, slice mushrooms 1/4 inch thick; cut each slice in half lengthwise.
- Heat roasting pan over medium-high heat for 1 minute.
- Pour in beef stock, stirring to scrape up any brown bits.
- Add mushrooms and simmer 10 minutes.
- Mix flour with vinegar and whisk into pan.
- Bring to a boil, whisking constantly until thickened.
- Season with salt and pepper to taste.
- Serve roast and sauce with small roasted potatoes and steamed vegetables.