Place roast skin-side down in a tray and pour boiling water halfway up
Bake for 20 minutes at 200°C (fan) / 392°F
Remove roast and go over the scoring so every cut runs edge to edge
Salt the skin heavily and the underside moderately
Pat the skin dry
Return to tray and season water with peppercorns, bay leaves, cloves, thyme, onions, and carrots
Use foil balls under the roast to level it perfectly
Roast for 1.5 hours at 200°C (fan) / 392°F, turning tray halfway and topping up water if needed
Rest for 30-40 minutes
Strain tray liquid and skim off the fat with a spoon
Make roux by combining 1 part butter and 1 part flour, cook until light brown
Add the strained jus to the roux
Finish sauce with heavy cream, red currant jelly, salt, and browning
Simmer sauce for 15 minutes to remove taste of flour
