Preheat your oven to 450°F (230°C). In a small bowl, combine the toasted cumin seeds, dried sumac, cracked black pepper, sea salt, minced garlic, and olive oil to form a paste.

Rub the spice paste all over the prime rib, ensuring an even coating. Let the meat sit at room temperature for about 30 minutes to 1 hour to enhance the flavor.

Place the seasoned prime rib on a rack in a roasting pan. Roast in the preheated oven for 15 minutes to develop a crust.

Lower the oven temperature to 325°F (165°C) and continue roasting for about 1.5 to 2 hours, or until the internal temperature reaches your desired doneness (125°F for medium-rare).

While the meat is roasting, prepare the confit butter by combining the softened butter, finely chopped rosemary, smoked paprika, sea salt, and lemon juice in a bowl. Mix well until fully combined.

Transfer the mixture to a piece of parchment paper and roll it into a log shape. Twist the ends to seal, then refrigerate until firm.

Once the prime rib reaches the desired temperature, remove it from the oven and let it rest for at least 20 minutes before slicing. This will help retain the juices.

Slice the prime rib into thick portions and serve topped with slices of smoked rosemary confit butter. Garnish with fresh rosemary sprigs if desired.