Remove the beef roast from the refrigerator 1 hour before cooking to let it come to room temperature.

Preheat the oven to 325°F (165°C). Line a roasting pan with foil and place a rack inside.

Pat the beef dry. Using a sharp knife, lightly score the top fat cap in a diamond pattern (do not cut deep into the meat). Rub the entire roast with olive oil, salt, and pepper.

Place the beef on the rack fat-side up. Roast for approximately 60-75 minutes, or until the internal temperature reaches 115°F (46°C).

While the beef bakes, combine pomegranate juice, brown sugar, tangerine juice, tangerine zest, Dijon mustard, and minced garlic in a small saucepan over medium heat.

Simmer the glaze for 10 minutes until slightly reduced. Whisk in the cornstarch slurry and cook for another minute until thickened. Remove from heat.

Once the beef reaches 115°F, remove it from the oven. Increase the oven temperature to 425°F (220°C).

Generously brush the thickened glaze over the top and sides of the roast. Return to the oven and bake for 10-15 minutes, watching closely to prevent burning, until the internal temperature reaches 125°F (52°C) for medium-rare.

Transfer the roast to a carving board/platter. Tent loosely with foil and let rest for 20 minutes before slicing thinly against the grain.

Garnish with fresh pomegranate arils and tangerine slices before serving.