Ingredients
1 1/2 cups all-purpose flour, plus more for work surface
1/2 teaspoon coarse salt
3/4 cup (1 1/2 sticks) unsalted butter, softened
3/4 cup sifted confectioners' sugar
1 large egg
1/4 cup (1/2 stick) unsalted butter, softened
2/3 cup sifted confectioners' sugar
Pinch of coarse salt
2 tablespoons chestnut cream (creme de marron)
6 ounces semisweet chocolate, coarsely chopped
Preparation
Make cookies: Sift together flour and salt into a medium bowl; set aside. Put butter in the bowl of an electric mixer fitted with the paddle attachment. Mix on medium-high speed until fluffy, about 2 minutes. Add sugar; mix until smooth. Mix in egg. Reduce speed to low. Add flour mixture; mix until just combined. Wrap dough in plastic, and refrigerate until firm, about 2 hours.
Preheat oven to 350 degrees. Roll out dough on a lightly floured work surface to 1/8 inch thick. Cut into 1 1/2-inch rounds. Using a spatula, transfer rounds to baking sheets lined with parchment paper, spacing 1 inch apart.
Bake cookies, rotating sheets halfway through, until edges are golden, about 12 minutes. Transfer to wire racks using a spatula; let cool completely.
Make filling: Put butter in the bowl of an electric mixer fitted with the paddle attachment. Mix on medium speed until smooth, about 3 minutes. Add sugar, salt, and chestnut cream; mix until smooth.
Make glaze: Melt chocolate in a small pan over low heat, stirring constantly; set aside.
Assemble cookies: Spread filling on bottom of half the cookies. Sandwich with remaining cookies. Repeat with remaining cookies and filling. Dip sandwiches a third of the way into the warm glaze; transfer to wire racks set over baking sheets. Refrigerate until set, about 15 minutes.
