I love a good prime rib roast – such a treat. Mustard and beef are perfect together, add a little horseradish in there and the house will smell amazing.
For about a 5 pound prime rib roast:
2 generous heaped tablespoons Dijon mustard
1 generous heaped tablespoon horseradish
2 cloves minced garlic
1 tsp kosher salt
1 tsp freshly cracked black pepper
1 tbsp. mustard seeds (lightly toasted first – and cracked)
finely minced parsley
blend all this together with 1 tbsp. good quality olive oil
Season prime rib with salt and pepper, then rub the mustard all over the surfaces of the rib. Allow to rest on the counter to bring the roast to room temperature before roasting.
Quarter 4 medium size onions, and scatter around the roast – drizzle with olive oil and any of the remaining mustard mixture.
Preheat oven to 450 degrees. Place roast in oven and roast for 20 minutes – then turn oven down to 350 and continue roasting – anywhere from 1-2 1/2 more hours depending on the size of your prime rib (you can also use this method with any other good quality cut of beef that does not require low slow roasting). Right about the same time the onions should be tender, sweet and so delicious.
Please make sure to use your meat thermometer – there is no point in overcooking a beautiful cut of beef! (for medium rare it should take about 20-25 min per pound)