Hollandaise sauce

Method

1.  Put the vinegar, peppercorns, bay leaf and mace into a small, heavy-bottomed saucepan over a low heat. Bring to the boil, then reduce the heat and simmer until reduced to about 1 tablespoon. Strain the reduced mixture into a heatproof glass bowl.
2.  Add the egg yolks to the strained reduction with 1 small cube of the butter and a little salt and freshly ground black pepper. Set over a pan of gently simmering water and whisk until slightly thickened. Remove the bowl from the heat if you have to leave it for any reason.
3.  Return the bowl to the pan of simmering water and whisk in the remaining butter, a few cubes at a time, until it’s all incorporated and you have a good thick sauce. If you think it’s too hot, take the pan and bowl off the heat and continue. Whisk in a good squeeze of lemon juice.