Pudding Puff Cake

Ingredients

• ⅓ cup (80 ml) water
• ⅓ cup (80 ml) whole milk
• 6 tablespoons (3 oz/85 g) unsalted butter, cut into 6 pieces
• 1 tablespoon granulated sugar
• ½ teaspoon fine sea salt
• ¾ cup (102 g) all-purpose flour
• 3 large eggs, at room temperature
• 1 large egg white, at room temperature
• 2 cups (480 ml) whole milk, for the pudding
• ½ cup (100 g) granulated sugar, for the pudding
• ¼ cup (22 g) unsweetened cocoa powder
• 3 tablespoons cornstarch
• ¼ teaspoon fine sea salt, for the pudding
• 4 ounces (113 g) dark chocolate, finely chopped
• 2 tablespoons unsalted butter, for the pudding
• 1 teaspoon pure vanilla extract
• 1 cup (240 ml) cold heavy cream
• 2 tablespoons confectioners’ sugar, plus more for dusting

Instructions

1. Make the pudding first. In a medium saucepan, whisk together the ½ cup sugar, cocoa powder, cornstarch, and ¼ teaspoon salt. Gradually whisk in the 2 cups milk until smooth. Cook over medium heat, whisking constantly, until the mixture bubbles and thickens, 6 to 8 minutes.
2. Remove the pudding from the heat and stir in the chopped dark chocolate, 2 tablespoons butter, and vanilla until glossy and smooth. Press plastic wrap directly against the surface and refrigerate until thoroughly cold, at least 2 hours.
3. Center a rack in the oven and preheat to 400°F (200°C). Line two 8-inch round cake pans, each at least 2 inches deep, with parchment paper. Do not grease the pans.
4. For the choux layers, combine the water, ⅓ cup milk, 6 tablespoons butter, 1 tablespoon sugar, and ½ teaspoon salt in a medium saucepan. Bring to a full boil over medium heat. Add the flour all at once and stir vigorously with a sturdy spoon until a smooth ball forms and a thin film appears on the bottom of the pan, about 2 minutes.
5. Transfer the dough to a mixer bowl and beat with the paddle on low for 1 minute to release steam. Add the 3 eggs one at a time, beating well after each. Beat in the egg white a little at a time until the dough is glossy, thick, and slowly falls from the paddle in a V shape.
6. Divide the dough evenly between the prepared pans. Spread it loosely across the bottoms, leaving natural swirls, peaks, and dips. Bake for 20 minutes without opening the oven, then reduce the temperature to 350°F (175°C) and bake for 18 to 22 minutes more, until the layers are deeply golden, crisp, and dry.
7. Turn off the oven, pierce each puff layer in several places with a thin knife to release steam, and leave them in the oven with the door slightly open for 10 minutes. Transfer to racks, remove from the pans, peel away the parchment, and cool completely.
8. Whip the cold heavy cream with 2 tablespoons confectioners’ sugar to medium peaks. Fold half of the whipped cream into the cold chocolate pudding to lighten it, keeping the remaining cream for serving.
9. Place one puff layer on a serving plate and spread the chocolate pudding filling generously over it. Top with the second layer, choosing the most dramatic side to face up. Refrigerate for at least 1 hour so the cake can settle.
10. Dust with confectioners’ sugar and serve with the remaining whipped cream. Use a serrated knife and a gentle sawing motion to cut the cake into 6 to 8 portions.