Preheat the oven to 320 °F.
Wash the whole piece of already cooked brisket under cold running water to remove any excess salt. It can be left to soak in a bowl of water for an hour, changing the water after 30 minutes. Pat dry with a paper towel.
Cut two large pieces of foil and position them in a roasting pan, one running lengthways and the other on top of it running widthwise.
Place the brisket in the centre of the pan.
In a bowl, mix all the glaze ingredients until well blended and pour over the brisket. You can sprinkle about a tablespoon of coriander over the sauce to give it that "pastrami" flavour.
Draw the sides of the foil up to the centre and ‘balloon’ the foil around the meat so that there’s a pocket of air between the meat and the foil.
Bake for about 1½ hours, by which time you should have a soft tender brisket coated in a lovely sticky glaze.
Slice and serve on fresh rye bread (On Pesach serve on a bed of mashed potato !) with the red cabbage and cucumber relishes below.
Cabbage Relish
Blanch the cabbage in a large saucepan of salted boiling water for 2 minutes. You literally drop all the cabbage into the boiling water, ensure it's immersed and then remove it once it's all been dunked.
Drain well in a colander and allow to cool.
Transfer to a large bowl and toss with the carrot, onion and paprika peppers. Set aside.
To make the dressing, whisk all the ingredients together in a bowl or shake up in a jar.
Once the sugar has dissolved, let it stand for 20–30 minutes, remove the bay leaf and pour over the red cabbage relish. Refrigerate if not using immediately.