Remove the leaves from the rosemary sprigs, leaving around 3cm of leaves at the tip. Remove the outer membrane from the stalk with a small knife, and cut the other end on an angle to make it easier to pierce the fish.

Thread the sole filets onto the rosemary skewers, turning them to make a twisting shape. Place two filets on each skewer. Set aside in the fridge.
Peel the white asparagus, leaving the green asparagus unpeeled, and trim the tough ends.
Bring some salted water to a boil and cook the white asparagus for 5-6 minutes. Remove, add some more water, and bring to the boil again to cook the green asparagus for 3-4 minutes.
Meanwhile, cook the sole in a non-stick frying pan with 20g butter for 2-3 minutes on each side until lightly golden.
Wash and chop the chervil and coriander. Remove the leaves from the thyme stalks. Heat the remaining butter in a small saucepan with the lemon juice. Bring to a boil and then add the herbs. Season with salt and pepper and return to the boil.

To serve, alternate the green and white asparagus on a plate and place the fish on top. Drizzle with the herb butter.