Soft Shell Crabs with Sorrel Recipe by Chef Carmen Quagliata of Union Square Cafe   INGREDIENTS (Serves 4) Sauce 1 tablespoon butter 2 teaspoons minced shallots 1 1⁄2 tablespoons white wine 1⁄2 cup heavy cream 1⁄2 teaspoon salt 3 twists of fresh black pepper 4 ounces sorrel leaves 2 tablespoons water   Crabs 2 tablespoons butter Salt Pepper 1 large leek, split, cut into 1⁄2” pieces, washed 2 cups fingerling potatoes, boiled in salted water until tender, cut into 1⁄4” thick slices 1 cup bacon lardons, cut into 1⁄4” dice, rendered, drained from fat 1 quart frying oil (either vegetable or canola) 4 jumbo soft...