Preheat your oven to 450°F (232°C).

In a small bowl, combine the cracked Sichuan peppercorns, kosher salt, black pepper, olive oil, smoked paprika, and garlic powder. Mix well to form a paste.

Rub the spice paste all over the prime rib roast, ensuring it is evenly coated. Let the roast sit at room temperature for about 30 minutes.

While the roast is resting, prepare the smoked herb butter. In a bowl, mix the softened butter, chopped herbs, smoked paprika, and lemon juice until well combined. Set aside.

Heat a large cast-iron skillet or oven-safe pan over high heat. Once hot, add the spring onions and char them for 2-3 minutes until they are nicely browned and slightly softened. Remove from the skillet and set aside.

In the same skillet, place the prime rib roast fat side up. Roast in the preheated oven for 15 minutes to develop a crust.

After 15 minutes, reduce the oven temperature to 325°F (163°C) and continue roasting for about 1.5 to 2 hours or until the internal temperature reaches your desired doneness (medium-rare: 130-135°F or 54-57°C).

During the last 30 minutes of roasting, add the charred spring onions to the pan with the roast.

Once cooked, remove the prime rib from the oven and let it rest for at least 20 minutes before slicing.

Serve slices of the prime rib with a dollop of smoked herb butter on top and the charred spring onions on the side.