200g/7oz baby spinach
3 spring onions, chopped
2 tsp English mustard
1 tbsp Worcestershire sauce
1 bay leaf
1 tbsp plain flour, plus extra to dust
15g/陆oz unsalted butter
250g/9oz cheddar, grated
2 free-range egg yolks
300ml/陆 pint milk
250g/9oz packet ready-made puff pastry
500g/1lb 2oz smoked haddock, skin on and pin boned
100ml/3陆fl oz IPA beer