Prepare the Roasted Garlic Confit: Preheat the oven to 300°F (150°C). In a baking dish, combine the peeled garlic cloves, olive oil, salt, and black pepper. Cover with foil and roast for 45 minutes to 1 hour, or until the garlic is soft and golden brown. Let cool and store in an airtight container in the refrigerator.

Prepare the Cracked Cardamom-Crusted Prime Rib: Take the prime rib out of the refrigerator and let it come to room temperature for about 1 hour. Preheat the oven to 450°F (232°C). Combine the cracked cardamom, kosher salt, black pepper, garlic powder, onion powder, rosemary, and thyme in a bowl. Rub this mixture all over the prime rib, ensuring even coverage.

Place the prime rib on a rack in a roasting pan, fat side up. Roast in the preheated oven for 20 minutes, then reduce the temperature to 325°F (163°C) and continue roasting for 1.5 to 2 hours, or until the internal temperature reaches 135°F (57°C) for medium-rare. Let rest for 20-30 minutes before slicing.

Prepare the Smoked Leek Compound Butter: In a mixing bowl, combine the softened butter, smoked leeks, lemon juice, smoked paprika, salt, and pepper. Mix until smooth. Transfer the compound butter to parchment paper and roll it into a log shape. Twist the ends to seal and refrigerate until firm.

Serve the sliced prime rib with a generous dollop of roasted garlic confit and slices of smoked leek compound butter on top. Enjoy!