8” White Boston Cream Cake Recipe

Prepare

Preheat oven to 350°F (175°C). Lightly grease and line the bottom of an 8-inch round cake pan with parchment; grease parchment. Have ingredients at room temperature (butter and eggs).

In a medium bowl whisk together 1.25 cups all-purpose flour, 1.5 tsp baking powder and 1/2 tsp fine salt. Set aside.

In a large bowl or stand mixer fitted with the paddle attachment, cream 6 tbsp softened unsalted butter and 1 cup granulated sugar on medium-high until light and fluffy, about 3–4 minutes, scraping the bowl once or twice.

Add 2 large eggs, one at a time, mixing well and scraping bowl between additions. Mix in 1 tsp vanilla extract.

With mixer on low, add the dry ingredients in three additions alternating with 1/2 cup whole milk: dry, milk, dry, milk, dry. Mix only until just combined and no streaks of flour remain; do not overmix.

Pour batter into prepared 8-inch pan and smooth top. Tap gently to remove large air bubbles.

Bake in preheated oven until a toothpick inserted in center comes out clean, about 25–30 minutes (oven times vary). Cake should be golden and spring back lightly when touched.

Remove cake from oven and let cool in pan on a wire rack for 10 minutes. Run a knife around edge, invert onto rack, remove parchment, then invert again so cake top faces up. Cool completely before filling, about 1–1.5 hours.

In a small saucepan, warm 1 cup whole milk over medium heat until it just starts to steam and small bubbles form at the edge; do not boil.

While milk warms, whisk together 1/3 cup granulated sugar, 3 tbsp cornstarch and a pinch of the 1/8 tsp salt in a medium bowl until smooth. Add 3 egg yolks and whisk until pale and slightly thickened.

Temper the yolk mixture: slowly pour about one-quarter of the hot milk into the yolks, whisking constantly. Then pour the tempered yolk mix back into the saucepan with the remaining milk, whisking continuously.

Return saucepan to medium-low heat and cook, whisking constantly, until mixture thickens and comes to a gentle boil (bubbles will appear and it will become glossy), about 2–4 minutes. Continue whisking and cook 30–60 seconds more to remove any starchy taste.

Remove from heat and whisk in 2 tbsp cold cubed unsalted butter, 1 tsp vanilla extract and the remaining 1/8 tsp fine salt until smooth and glossy.

Strain the pastry cream through a fine-mesh sieve into a clean bowl to remove any lumps. Press a piece of plastic wrap directly onto the surface to prevent a skin from forming. Chill in refrigerator until completely cold and set, at least 2 hours (can be made a day ahead).

Chop 4 oz semi-sweet chocolate finely and place in a heatproof bowl.

In a small saucepan or in the microwave, heat 1/4 cup heavy cream until it just begins to simmer. Pour hot cream over the chopped chocolate and let sit 1 minute to soften.

Stir gently until chocolate is fully melted and smooth. Stir in 1 tsp light corn syrup and 1 tbsp unsalted butter, if using, to create a shiny, pourable glaze. If glaze is too thick, add up to 1 tsp warm cream; if too thin, let sit to thicken slightly.

Cool glaze slightly until it is warm but not hot, so it will spread without melting the pastry cream excessively.

If desired, brush the cooled cake top lightly with 2 tbsp simple syrup to add moisture and help the filling adhere.

Place the cooled cake on a serving plate or cake board with the top facing up (the smooth/top surface will become top of cake). Using a long serrated knife, slice the cake horizontally through the middle to create two thin layers: a bottom layer and a top layer. For a single-layer filling, you can split the cake into two thin layers and only use the base and top; alternatively, if you prefer a single whole layer of sponge, slice off a thin layer from top so you can pipe the pastry cream onto the center.

Spoon or pipe the chilled pastry cream onto the bottom cake layer in an even layer, leaving about 1/4 inch of margin at the edge to prevent overflow. Smooth with an offset spatula to an even thickness (about 1/2 inch to 3/4 inch, depending on preference).

Carefully place the cake top layer back over the pastry cream, pressing gently and evenly to remove air pockets.

Pour the warm (not hot) chocolate glaze over the center of the assembled cake and use an offset spatula to gently coax glaze toward the edges so it covers the top. Allow some glaze to slightly drip down the sides if desired.

Let the glaze set at room temperature for 30–60 minutes, or refrigerate briefly (10–15 minutes) to speed setting. Dust edges lightly with confectioners' sugar if desired just before serving.

Slice with a sharp knife dipped in hot water and wiped dry between cuts for clean slices. Store leftovers covered in the refrigerator for up to 3 days; bring to near room temperature before serving for best texture.