Serves 4-6

1 medium bulb fennel
250g green asparagus spears
2 little gem lettuces
1 large ripe avocado
about 25g Parmesan shavings (optional)

Dressing
300ml vegetable or chicken stock
2 sprigs fresh rosemary
4 tablespoons double cream
1 tablespoon fresh lemon juice
about 4 tablespoons vinaigrette
sea salt and freshly ground black pepper

Slice the fennel lengthways wafer-thin (a mandolin helps), then soak in ice-cold water for 20 minutes and drain.

Peel the asparagus stalks with a swivel peeler almost to the tips. Blanch in boiling salted water for 2 minutes, then drain and plunge into a bowl of iced water for 5 minutes. Drain again and pat dry. Separate out the lettuces and tear the leaves into bite-sized pieces. Add to the asparagus. Keep chilled in a plastic container or picnic bowl.

For the dressing, bring the stock to the boil in a small saucepan with one of the rosemary sprigs. Strip the leaves from the other sprig and chop finely. Set aside. When the stock has reduced by three quarters to around 5 tablespoons, add the cream and boil to reduce until the liquid is about 6 tablespoons. Cool, mix in the chopped rosemary, lemon juice and seasoning, then dilute with the vinaigrette. Pour this sauce into a container and keep chilled until ready to serve. At the picnic, peel, stone and slice the avocado and mix into the asparagus and lettuces. Toss in the dressing and top with Parmesan.

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