250g/9oz leeks, trimmed and sliced into 2cm/¾in-thick rounds
1 lemon, zest only
a few fresh sage leaves
1 tsp rubbed sage or ½ tsp dried sage
150ml/5fl oz chicken stock
1 tbsp plain flour
1 tsp baking powder
½ tsp mustard powder
salt
225g/8oz self-raising flour, plus extra for dusting
a few white peppercorns, crushed
knob of butter, for greasing
100–150ml/3½fl oz–5fl oz milk
100²µ/3½´Ç³ú suet
500g/1lb 2oz diced chicken (a mixture of skinned thighs and breasts)
100ml/3½fl oz white wine or vermouth