01 -
Take the roast out 2 hours ahead of cooking time. Dry it with paper towels and rub salt all over, even on the sides and bones. Put it in your pan with bones facing down and fat side up.
02 -
Stir the whipping cream, sour cream, horseradish, black pepper, salt, and cayenne together in a bowl until everything's combined. Wrap and stick in the fridge until you're ready to eat.
03 -
Put your oven rack in the middle and turn the heat to 500°F.
04 -
Pop the roast in for 15 minutes. There'll be smoke, so crank up your fan and maybe crack some windows.
05 -
Turn the heat down to 325°F and let it cook about 13 minutes per pound (roughly 1.5-2 hours) until it hits 115°F inside for rare or 120-130°F for medium.
06 -
Pull it out, move it to a cutting board, loosely cover with foil and don't touch it for 30 minutes.
07 -
Cut off the string or separate meat from bones. Cut across the grain into 1/2-inch slices. Dish it up with the cold horseradish sauce.