Steamed Fillets of Sole with Parsley Sauce

FOR THE FILLETS:
Rinse the sole and dry it. Season on both sides with salt and pepper. Use half the butter to coat a large sheet of parchment (baking) paper and spread the parsley in the center of it. Place the sole on top with the fleshier side down. Top with the lemon slices and the remaining butter cut into bits. Fold the paper to enclose the fish. Lay the parcel in a steaming basket and cook for 20 minutes over boiling water.

FOR THE SAUCE:
In a nonreactive small saucepan, combine the shallots with the vermouth. Reduce over gentle heat, then pour in the cream. Cook until reduced by half. Season with salt and pepper.

When the sole is cooked, remove the fillets and put them onto 2 hot plates. Garnish with the lemon slices. Put the cooking juices from the paper case into the saucepan and boil to reduce by half.

TO SERVE:
Transfer the sauce to a blender and add the olive oil; blend until smooth. Coat the fish fillets with the sauce. Serve immediately, accompanied by steamed potatoes.