Ingredients
8 ounces bittersweet chocolate (preferably 61 percent cacao), finely chopped
3/4 cup heavy cream
1/2 cup clover honey
1/2 vanilla bean, seeds scraped, pod reserved
3 tablespoons unsalted butter, softened
Unsweetened Dutch-process cocoa powder, for dusting
3 cups all-purpose flour, plus more for sheets
1/3 cup turbinado sugar
1 tablespoon baking powder
1/4 teaspoon ground cloves
1/4 teaspoon ground allspice
1 teaspoon coarse salt
1 can (15 ounces) solid-pack pumpkin
1/4 cup heavy cream
1 tablespoon pure vanilla extract
8 ounces (2 sticks) unsalted butter, softened, plus more for sheets
3 cups granulated sugar
4 large eggs, room temperature
1 large egg yolk, room temperature
Preparation
Make the petits fours: Preheat oven to 350. Butter 2 rimmed baking sheets. Line with parchment, butter and flour parchment, and tap out excess.
Whisk flour, turbinado sugar, baking powder, cloves, allspice, and salt in a large bowl. Whisk pumpkin, cream, and vanilla in a medium bowl.
Beat butter and granulated sugar with a mixer on medium-high speed until pale and fluffy, about 5 minutes. Add eggs, 1 at a time, and yolk, beating well after each addition, scraping down bowl as needed. Reduce speed to low, and add flour mixture in 3 additions, alternating with pumpkin mixture, starting and ending with flour mixture. Raise speed to medium, and beat until well combined. Divide batter evenly between sheets.
Bake, rotating sheets halfway through, until a toothpick inserted in centers comes out clean, about 25 minutes. Let cool in sheets on wire racks for 30 minutes. Run a knife around edges of cakes, invert cakes onto racks, and remove parchment. Let cool. Invert cakes onto parchment-lined baking sheets, cover each with plastic, and refrigerate for at least 4 hours or preferably overnight.
Make the glaze: Place chocolate in a food processor. Bring cream, honey, and vanilla seeds and pod to a simmer in a small saucepan, whisking until combined. Remove from heat, cover, and let steep for 15 minutes. Return cream mixture to a simmer, then pour through a fine sieve over chocolate. Process until completely smooth. Transfer to a bowl, and whisk in butter. Cover with plastic until ready to use. (Stir gently before glazing cakes.)
To assemble: Cut each cake horizontally into thirds to create thin layers. Spread 1/3 cup glaze on top of 1 cake layer, and gently press a second cake layer on top. Repeat layering once to create a 3-tiered cake. Repeat with remaining layers to create a second cake. Pour remaining glaze on top of cakes. Refrigerate until very firm, about 1 1/2 hours (or overnight).
Using a serrated knife, trim each cake into a 5-by-11 1/4-inch rectangle, reserving trimmings for another use. Cut each rectangle into 1 1/4-inch squares, wiping knife clean frequently. Just before serving, dust with cocoa powder.
