Step 1

In a large nonstick frying pan, melt the butter over moderate heat. Sprinkle the sole with 1/2 teaspoon of the salt and the pepper. Dust the sole with the flour and shake off any excess. Put the sole in the pan and cook for 2 minutes. Turn and cook until just done, about 2 minutes longer. Remove the sole from the pan.

Step 2

Add the cream and lemon zest to the pan. Bring to a simmer and cook until starting to thicken, about 2 minutes. Stir in the remaining 1/4 teaspoon salt, the lemon juice, and parsley. Serve the sauce over the fish.