To make the sauce whisk together egg yolks, wine and Vegeta until frothy. Cook using indirect heat (over boiling water) whilst whipping continuously.
When the sauce thickens, remove from heat and progressively stir in the melted butter and lemon.
Boil the asparagus in salted water.
Wrap a few asparagus sticks in proscuitto and quickly fry in a non-stick pan.
Cook the vegetables in salted water.
Pour the sauce over the warm asparagus and vegetables and serve.
Prepare the sauce just before serving.