Preheat the oven to 200 degrees Celsius (400 degrees Fahrenheit).

Place the meat on a roasting rack in a roasting pan, cover in the oil and rub all over with the crushed peppercorns so that it’s evenly covered.

Roast the meat in the oven, uncovered, for one hour and 15 minutes (for every extra pound of meat, increase the cooking time by 15–20 minutes). If you don’t have a roasting rack in your roasting pan, turn the roast over halfway through cooking.

Place the potatoes (skin on or off) in a roasting bag with the rosemary and a few glugs of oil. Place on the side of the roasting pan with the meat when there is 1 hour of cooking time remaining.

When done, remove the meat from the oven, cover in foil and leave to stand for 15 minutes while you make the horseradish cream. The horseradish cream can be made the day before and warmed up when needed.

Combine the sugar, potato flour, water, non-dairy creamer and salt in a mixing bowl and whisk well.

Pour the mixture in a saucepan and heat through, whisking all the while, until it starts to thicken. Remove from the heat, add the horseradish and stir.

Serve with the meat and rosemary potatoes.