Makes 25 sandwich cookies

Ingredients

Cookies

• 2/3 cup butter, room temperature
• 1 cup powdered sugar
• 2 large egg yolks
• 1 teaspoon vanilla extract
• ½ Tonka bean, grated (optional)
• 2 cups All-purpose flour
• 2 Tablespoons freshly ground coffee
• ½ teaspoon Kosher salt

Filling

• 4 oz semi-sweet chocolate, chopped
• 1/3 cup heavy, or whipping, cream
• 1 Tablespoon butter

Method

1. In the bowl of a stand mixer fitted with the paddle attachment, beat softened butter until creamy. Add confectioners’ sugar and beat until well combined and smooth
2. Add egg yolks, vanilla extract and beat just until fully combined
3. Add flour, ground coffee, salt, and beat at low speed just until flour is incorporated but before dough forms a ball
4. Turn out dough onto a floured surface and use your hands to bring dough together. Divide dough in half and roll into 1½-inch-wide logs. Wrap logs in cling wrap, and refrigerate until firm, 1 to 2 hours
5. Preheat oven to 350°F. Line baking sheets with parchment paper, or silicone making mats
6. Unwrap logs and cut into ¼-inch-thick rounds. Place rounds 1 inch apart on prepared pans
7. Bake until just lightly browned around the edges, 10 to 12 minutes. Let cool on pans for 5 minutes. Remove from pans and let cool completely on wire racks
8. Place chocolate in a large heatproof bowl. In a small saucepan, bring cream and butter to a simmer over medium heat. Pour hot cream mixture over chocolate. Let stand for 1 minute; stir until a smooth, silky ganache forms. Let stand until thickened, 30 minutes to 1 hour
9. Using a piping bag fitted with a small round piping tip, pipe a round of ganache onto flat side of half of cookies. Place remaining cookies, flat side down, on top of ganache. Let stand until ganache is set, 1 to 2 hours
10. Unfilled cookies will keep for 2 to 3 days. Once they are filled with ganache, the cookies are best served within a day