[1]For the Shrewsbury sauce:
2 level tablespoons plain flour
1 heaped teaspoon mustard powder
1 pint (570 ml) Beaujolais or other light red wine
5 rounded tablespoons good-quality redcurrant jelly, such as Tiptree
3 tablespoons Worcestershire sauce
juice 1 lemon
salt and freshly milled black pepper