Preheat the oven to 200C/gas mark 6. Put 4 skin-on, bone-in chicken thighs (about 500g) in a roasting tin, drizzle with a little olive oil, season with salt, pepper and 1-2 tsp of chopped thyme leaves and then roast for about 30 minutes, until the skin is golden. Remove from the oven and allow to cool.
Make the herb mayonnaise. Cut 150g of asparagus into short lengths, then cook in deep boiling water for about 7 minutes, or until tender, then drain and set aside. Peel a 70g piece of cucumber, cut in half, discard the seedy core, then cut the cucumber into thick matchsticks.
Put 5 heaped tbsp of mayonnaise in a mixing bowl and stir in 1 tsp of wasabi paste. Finely chop enough mint leaves to give you 2 heaped tbsp (the leaves from about 10g of mint sprigs) and add to the mayonnaise. Finely chop a small bunch (8g) of dill fronds and stir into the mayonnaise with a little salt. Slice and add 4 radishes.
Remove the skin from the chicken thighs and set aside. Slice the meat from the bones and roughly chop, then stir lightly into the herb mayonnaise together with the asparagus and cucumber.
Set a frying pan over a moderate heat, then add the chicken skin and cook for 3 or 4 minutes until crisp, then turn and cook the other side. Salt generously and place on a piece of kitchen paper.
Add 1 tbsp of pine nuts to the pan in which you cooked the chicken skin and fry for a minute or so until golden. Remove the pine nuts and set aside, add a couple of tbsp of the fat from the roast chicken tin to the frying pan, slice 4 brioche or white buns in half and toast the cut sides in the fat. Add a little olive oil if the pan is dry. Place the bottoms of the buns on plates and fill with the chicken and asparagus and herb mayonnaise. Top with the reserved bun halves. Serves .
Only the generous can make a sandwich worth eating. The chicken is best at room temperature rather than cold from the fridge. I like to put any salad leaves or radishes into a deep bowl of iced water for 20 minutes to crisp them up beforehand.
You can use chopped fresh chilli or 1 tsp or more of chilli paste in place of the wasabi or a make a curried mayonnaise by adding a spoonful of curry paste. If I do that, then I also include some sliced peach or mango, too.