- 1.8kg boneless prime rib beef roast
- 6 garlic cloves, minced
- 2 tablespoons whole grain Dijon mustard
- 1 tablespoon fresh thyme leaves
- 1/3 cup kosher salt
- 1/4 cup freshly ground black pepper
- 1/4 cup extra-virgin olive oil, plus 3 tablespoons for the vegetables
- 900g small potatoes, halved if larger than 3 inches
- 900g assorted root vegetables (such as carrots, beets, turnips or parsnips), peeled and sliced on the bias
- 2 tablespoons all-purpose flour
- 1 litre beef stock
- 2 sprigs fresh thyme
Allow the roast to rest at room temperature at least 30 minutes. Preheat oven to 180°C.
Mince the garlic cloves. Combine with Dijon mustard, thyme, salt, pepper and olive oil to create a rub. Spread evenly over the prime rib, patting it well. Place the roast fat side up in the roaster.
In a bowl, toss the potatoes and root vegetables with olive oil. Season generously with salt and pepper. Arrange the vegetables around the roast, reserving any tender vegetables, such as carrots, for later.
Place the roaster in the center rack of the oven. Roast until internal temperature reaches 50°C. Add the more tender vegetables to the pan about halfway through roasting. When the roast is ready, remove from the oven and let rest 20 minutes before carving.
While the roast rests, make the jus (gravy). Discard a few tablespoons of fat, leaving some in the roaster. Place the roasting pan over medium heat. Whisk in the flour, stirring constantly for about 3 minutes, until it reaches a paste consistency.
Pour in the beef stock and add thyme, stirring continuously. Use a wooden spoon to release any browned bits on the bottom of the roaster.
Increase the heat to high and continue to cook, whisking periodically, until the sauce reduces, about 10 minutes. Adjust seasonings if necessary, and strain the jus to serve with the roast.