Instructions: Heat oven to 400 degrees. Lightly butter a heavy cookie sheet.

In bowl of an electric mixer with the paddle attachment, cream the butter. Add the sugar and continue to beat until creamy, about 2 to 3 minutes. Sift the flour 3 times with the salt. Beat in the egg whites, one at a time. Add the vanilla. Scrape down the sides of the bowl with a rubber spatula. Add flour gradually, scraping down the sides. Stir in the lemon zest.

Transfer the batter to a large pastry bag fitted with a #2B tip and a large size coupler. Pipe out cookies in an "s" shape, about 3-inches long. Repeat "s" pattern in reverse. Bake until the edges are golden brown, about 12 to 15 minutes. Transfer to a cooling rack. They will become crisp as they cool.

Combine the chocolate and corn syrup in a double boiler over simmering water; stir occasionally with a rubber spatula until smooth. Using a small offset spatula or knife, spread cookie with chocolate and top with another cookie to form a sandwich. Dip about 1 inch of each cooled cookie into chocolate and roll to coat with pistachios, let dry.

This recipe yields about 5 dozen 3-inch cookies.

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