Heat the butter in small saucepan and sizzle the shallots and garlic gently with a pinch of salt for 3-4 mins, until softened. Add the flour and cook, stirring, for another 2-3 mins until you have a light, sandy paste.

Increase the heat, add the wine and bubble for 3 mins, until reduced by about two-thirds. Pour in the stock and bubble for another 3-4 mins, until reduced by half again, then stir in the cream. Reduce the heat and simmer for 1 min until you have a silky, thickened sauce. Season to taste. You can strain the sauce at this point to remove the shallots but this is optional. Will keep chilled for two days or frozen for up to a month. Defrost thoroughly before reheating in a small pan over a low heat. Finish with a handful of chopped herbs, if you like.