In a small saucepan melt 5 tablespoons of the butter over moderately low heat. With a spoon remove the foam off the top and discard. Spoon the clear butter into a small bowl leaving any milky-watery residue at the bottom of the saucepan. Discard the residue. The clear butter is clarified butter and has a higher smoking point now that the milk solids have been removed.
Clean the soft shell crabs by first cutting away the eyes and mouth. Lift up the top side flaps and pull out the feathery gills. Turn the crab over and fold back the tail flap, also called the apron, and pull away from the body and discard. Place crabs in a shallow dish and add enough milk to cover. Soak crabs for 10 to 15 minutes.
Preheat oven to 400 degrees F.
Season each crab with salt and pepper. Dredge each crab in the flour and shake off any excess. In a heavy large skillet heat the clarified butter over moderately high heat until hot but not smoking. Carefully place the crabs in the skillet, shell-side down; they tend to sputter and pop. Cook the crabs until they begin to blister and then flip. Transfer skillet to the preheated oven and bake for 2 to 3 minutes.
Meanwhile, in a separate skillet melt the remaining 3 tablespoons of butter over moderate heat and cook until the butter just begins to brown. Add the sherry vinegar and remove from the heat. Add the chopped nuts and blanched peas, tossing to coat and combine. Season to taste with salt and freshly ground pepper.
Place a crab on each serving plate and top with brown butter sauce, nuts and peas.
Recipe courtesy of Gourmet Magazine