12 asparagus spears, woody ends snapped off
1½ tbsp chopped lemon thyme leaves
1 large lemon, juice only
2 tbsp chopped parsley
6 banana shallots, quartered lengthways
400ml/14fl oz chicken stock
30g/1oz plain flour
salt and freshly ground black pepper
2 tbsp oil
50g/1¾oz butter
200ml/7fl oz full-fat crème fraîche
6 small chicken breasts, boned, skinned