Remove the prime rib from the refrigerator and let it sit at room temperature for about 1 hour before cooking.

Preheat your oven to 500°F (260°C).

In a small bowl, mix together the smoked mulato chili powder, crushed toasted cumin seeds, kosher salt, and black pepper.

Rub the olive oil all over the prime rib, then generously season it with the spice mixture, ensuring all sides are evenly coated.

Place the prime rib on a roasting rack in a large roasting pan, bone side down.

Roast in the preheated oven for 20 minutes to sear the outside.

Reduce the oven temperature to 325°F (163°C) and continue roasting for approximately 1.5 to 2 hours, or until the internal temperature reaches 130°F (54°C) for medium-rare, or your desired doneness.

Once cooked, remove from the oven and let the roast rest for at least 20-30 minutes before carving.

In a skillet over medium heat, add olive oil. Add the sliced leeks and sprinkle with salt and pepper.

Cook the leeks, stirring occasionally, until they are soft and caramelized, about 15-20 minutes.

In a bowl, combine the softened butter, caramelized leeks, thyme, parsley, and lemon zest. Mix well until fully incorporated.

Transfer the compound butter onto a sheet of parchment paper, shape into a log, and refrigerate until firm.

Slice the rested prime rib and serve with slices of the caramelized leek compound butter on top. Enjoy with your favorite sides!