Method

• 1.
  Preheat oven to 180°C. Place duck fat in a deep roasting pan and place in oven to heat. Leave in oven until needed.
• 2.
  Meanwhile, place potatoes in a saucepan and cover with cold water. Place over high heat and bring to the boil, then reduce to a simmer and simmer for 7 minutes to partially cook. Drain, return potatoes to pan and shake pan gently to rough up outside of potatoes. Remove duck fat tray from oven and, working quickly, carefully transfer potatoes to duck fat and stir to coat. Return to oven and roast, turning halfway, for 1 hour 30 minutes or until golden.
• 3.
  To make the sauce, bring stock to a simmer in a large frypan over high heat, gradually whisk in butter, 1 piece at at a time, until all butter is added and well combined. Remove from heat.
• 4.
  Heat extra duck fat in a second large frypan over high heat. Add pancetta and cook, stirring occasionally, for 3 minutes or until golden. Add cabbage and cook, stirring occasionally, for 2 minutes or until wilted. Return sauce to medium heat, add pancetta mixture and stir until well combined. Fold through radicchio and potatoes to serve.