Sage and Onion Sauce

Method

• step 1

  Preheat the oven to 230C/Gas 8/fan oven 210C. Brown the duck bits in the oven for about 30 minutes. Transfer to a stockpot. Discard the fat and place the tin over a medium-high flame. Pour in the Marsala and 200ml/7fl oz cold water, bring to the boil and scrape any stuck-on bits into the liquid. Boil for 2 minutes then scrape everything into the stockpot.

• step 2

  Add 2.25 litres/4 pints cold water to the pot and bring to the boil over a medium heat, uncovered. Scoop off any scum, then add the vegetables and herbs. Bring back to the boil, de-scum again.

• step 3

  Now very gently simmer for 2 hours, adding cold water if the liquid falls below the level of the bones. Remove from the heat and drain through muslin-lined colander (or use a clean tea towel) into a heatproof bowl. Cool, then refrigerate until jellied.

• step 4

  Heat the butter and oil in a large, nonstick frying pan over a low-medium heat, then tip in the onions. Cook for about 30 minutes, stirring occasionally, until meltingly soft. Turn heat to high, add the Marsala and boil for 3-4 minutes, stirring often, until onions are syrupy. Set aside.

• step 5

  Meanwhile, remove the solidified fat from the stock and discard. Boil the stock in a saucepan, uncovered, until reduced to 500ml/18fl oz. Add the white wine and boil for 10 minutes, uncovered. Add the onions and sage and bring back to the boil. (Prepare in advance up to this point.)

• step 6

  To finish the sauce, pour in the cream and boil furiously for 4-5 minutes, season to taste. Serve in a warmed jug.