Season prime rib roast liberally with salt and pepper all over. Place dried porcinis in a food processor or blender, and process until they are a fine powder. Combine chile powder, garlic powder, onion powder, and paprika with powdered porcinis. Sprinkle rub all over the seasoned prime rib roast. Roast in a 275 degree oven until you reach an internal temperature of 110 degrees for rare, 120 degrees for medium rare, and 130 for medium. Pull out of oven and crank oven up to 500 degrees. Cover roast with foil for at least 30 minutes or until the temperature stops going up. While roast is resting, separate out Â½ cup of liquid from the roast, from the fat and set aside. Heat a sautÃ© pan over high heat and get it really hot, add 1-2 tablespoons butter to hot pan, and then add the mushrooms and sautÃ© until brown and cooked. Deglaze pan with the red wine, and reserved roast liquid. Reduce down by at least half, or until slightly thickened. Pull the pan off the heat, and whisk in cold butter, until the sauce becomes nape. Taste the sauce, and adjust the seasoning accordingly with salt and pepper. Keep the sauce just barely warm, to keep it from breaking. Meanwhile, take the foil off the roast after it has rested 30 minutes, and then put in in the 500 degree oven for about ten minutes or until it gets nice and caramelized. Remove from the oven. Slice prime rib, and serve with the sauce on top.