Preheat your oven to 450°F (230°C).

In a mixing bowl, combine the toasted walnuts, cracked mustard seeds, fresh rosemary, fresh thyme, minced garlic, olive oil, salt, and pepper. Mix well to create a crust mixture.

Season the prime rib roast generously with salt and pepper. Place it on a roasting rack in a roasting pan.

Press the walnut and mustard seed mixture evenly over the top and sides of the prime rib roast, ensuring it adheres well.

Roast the prime rib in the preheated oven for 20 minutes to develop a nice crust. Then, reduce the oven temperature to 325°F (165°C) and continue roasting for approximately 1.5 to 2 hours, or until the internal temperature reaches your desired doneness (130°F for medium-rare).

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

While the roast is resting, prepare the smoked paprika gravy. In a saucepan, melt the butter over medium heat. Stir in the flour and cook for 1-2 minutes until lightly golden.

Gradually whisk in the beef broth and red wine, ensuring there are no lumps. Add the smoked paprika, and season with salt and pepper to taste. Bring to a simmer and cook for about 5-7 minutes until thickened.

Slice the prime rib and serve it with the rich smoked paprika gravy drizzled over the top.