Truffle oil varies greatly in strength so make sure to taste as you go when making the truffle butter. For the crayfish, bring 4 litres/7 pints water to the boil. Add the stout, salt, sugar ...

To prepare the truffle ... as the liquid evaporates (4), salt (5), and cook the risotto: it will take about 18-20 minutes. When the risotto is ready, turn off the heat, stir in the butter off ...