Beef Rib Roast with Mushrooms & Fennel

Combine 4 1/2 teaspoons salt and mushroom powder in a small bowl. Rub the mixture all over meat. Place the roast fat-side up on a rack in a roasting pan. Refrigerate, uncovered, for 1 day or up to 3 days.

When ready to continue, let the roast stand at room temperature for 1 hour before cooking. Preheat oven to 325 degrees F.

Finely chop enough fennel fronds to make 6 tablespoons (reserve bulbs). Combine the fronds, garlic, rosemary, ground fennel, crushed red pepper, lemon zest and 6 tablespoons oil in a small bowl. Rub the mixture all over the roast (but not the bones).

Roast the meat until an instant-read thermometer inserted in the thickest part without touching bone registers 125 degrees F for medium-rare, 2 to 3 hours.

Transfer the roast on the rack to a cutting board, tent with foil and let rest for at least 30 minutes.

Meanwhile, increase oven temperature to 450 degrees . Pour 1/2 cup of the drippings from the roasting pan into a medium bowl. (If necessary, add oil to measure 1/2 cup total.)

Trim, core and slice the fennel bulbs. Add to the drippings along with mushrooms, shallots and thyme sprigs; toss to coat. Divide the mixture between 2 large rimmed baking sheets. Roast, stirring occasionally, until lightly browned and tender, 20 to 30 minutes. Discard the thyme.

Combine pine nuts and vinegar with the remaining 1/2 teaspoon salt and 1 tablespoon oil in a mini food processor. Pulse until mostly smooth.

Transfer the roasted vegetables to a serving bowl and toss with the vinaigrette. To carve the roast, remove the bones by slicing along their contours between the meat and the bone. Thinly slice the beef crosswise and serve with the vegetables. Garnish with more thyme, if desired.