Rum Squares Recipe
- 4 extra-large eggs
- 1 cup sugar
- Pinch of salt
- 1 1/4 cups cake flour
- 2 sheets frozen puff pastry, thawed according to manufacturer’s directions
- Egg wash
- 2 cups whole milk
- 3/4 cup sugar
- 1/2 cup cornstarch
- 6 extra-large egg yolks
- 2 teaspoons pure vanilla extract
- 8 tablespoons (1 stick) unsalted butter, cut into 8 pieces
- 1/4 cup coarsely chopped semisweet chocolate, for the Chocolate Pastry Cream
- 1 cup sugar
- 1 cup water
- 1/2 cup dark rum
- MAKE THE SPONGE CAKE
- Preheat the oven to 350°F. Line an 11 x 9-inch quarter-sheet pan with parchment paper.
- Combine the eggs, sugar, and salt in a stainless-steel bowl set over a saucepan of simmering water. Lightly whisk until the temperature of the mixture reaches 110°F. This will help add volume to your sponge.
- Transfer the egg mixture to the bowl of a stand mixer fitted with the wire whisk attachment (or use a hand mixer), and whip on high speed until very light, pale, and thick, 10 to 12 minutes. I always set a timer for this stage because it is so important.
- Carefully fold in flour, a quarter at a time, being careful not to deflate the foam.
- Spread the batter into the prepared pan.
- Bake the cake for 15 to 20 minutes, or until golden brown and the center springs back when touched.
- Remove the pan from the oven. Cool the cake in the pan completely before assembling. (The cake can be made and frozen 2 weeks in advance. Thaw before assembly.)
- BAKE THE PASTRY
- Preheat the oven to 400°F.
- Place the puff pastry sheets on a parchment paper-lined baking sheet. Prick the pastry with a fork and brush with egg wash.
- . Bake the pastry for 15 to 20 minutes, or until golden brown, pricking the pastry with a fork every 5 minutes. This will keep the pastry flat
- MAKE THE PASTRY CREAM
- . In a medium saucepan over low heat, bring 1 cup milk and 1/2 cup sugar just to a boil. In a mixing bowl, whisk cornstarch, egg yolks, remaining 1/4 cup sugar, and remaining 1 cup milk.
- . Slowly whisk hot milk mixture into egg mixture in a thin stream. Return the mixture to the pan and whisk constantly over low heat until boiling and thick. Remove from the heat and stir in the vanilla and butter.
- . Transfer half the mixture to a small bowl and place a piece of plastic wrap directly on the surface to prevent a skin from forming on top. Cool completely before using.
- . Add the chocolate to the remaining half of the mixture and stir until the chocolate has melted and the mixture is smooth. Transfer to a small bowl and place a piece of plastic wrap directly on the surface to prevent a skin from forming on top. Cool completely before using. (The pastry cream can be made 1 to 3 days in advance. Place in an airtight container and refrigerate.)
- MAKE THE RUM SYRUP
- . In a medium saucepan over medium heat, bring the sugar and water to a boil. Boil until the sugar has dissolved, 3 to 4 minutes. Remove from the heat and stir in the rum.
- ASSEMBLE THE RUM SQUARES
- . Spread the chocolate pastry cream over one layer of puff pastry. Top with the layer of sponge cake. Brush and soak the sponge cake with rum syrup. Spread a layer of vanilla pastry cream on top of the sponge cake and top with the remaining layer of puff pastry. Refrigerate for 2 to 3 hours or overnight. Slice into 2-inch squares with a serrated knife. Place in paper liners, if desired.