4. Heat half the butter in the cleaned shallow pan and add the shallot. Cook very gently for 5 minutes until soft but not coloured, then pour in the alcohol and boil until reduced to a few tablespoons. Pour in the poaching liquid and boil down until reduced by half, about 20-25 minutes. Stir in the cream and, once more, reduce by half. Turn down to a gentle simmer and whisk in the rest of the butter.