Cut the tips away from the asparagus
stalks, then cook the tips in boiling water for
2 mins before plunging into iced water. Cook
the stalks for 30 secs, then plunge into iced
water, too. Mix the olive oil, lemon juice and
lemon thyme together in a bowl and season
with pepper. Using a swivel-blade vegetable
peeler, strip ribbons off the stalks, dropping
them into the bowl of dressing as you go.
To serve, place a pile of asparagus ribbons
in the centre of each plate. Drape the
prosciutto around the side, scatter over the
asparagus tips and Parmesan, then drizzle
with some dressing from the bowl.