2 onions, thinly sliced
1 tbsp finely chopped fresh thyme leaves
1 tsp Dijon mustard
plain flour, for dusting
1 tbsp plain flour
1 heaped tsp redcurrant jelly
1 tbsp balsamic vinegar
300ml/陆 pint hot beef stock
salt and freshly ground black pepper
1 tbsp light muscovado sugar
1 tbsp olive oil
1 free-range egg, beaten
375g/13oz ready-rolled puff pastry
750g/1lb 10oz venison fillet, from the thickest end, trimmed
100ml/3陆fl oz port or red wine