This Boston Cream Sheet Cake is a dreamy, crowd-pleasing dessert layered with soft vanilla cake, rich creamy custard, and topped with a silky chocolate glaze—every bite melts in your mouth and tastes just like the classic Boston cream pie, but easier to make and perfect for sharing.
Ingredients
Vanilla Sheet Cake
- 2 ½ cups 315 g all-purpose flour
- 2 ½ tsp baking powder
- ½ tsp salt
- ¾ cup 170 g unsalted butter, softened
- 1 ¾ cups 350 g granulated sugar
- 4 large eggs
- 1 tbsp vanilla extract
- 1 ¼ cups 300 ml milk
Pastry Cream Filling
- 2 cups 480 ml whole milk
- ½ cup 100 g granulated sugar
- 4 large egg yolks
- ¼ cup 30 g cornstarch
- 2 tbsp unsalted butter
- 1 ½ tsp vanilla extract
Chocolate Ganache Topping
- 1 cup 170 g semi-sweet chocolate, chopped
- ¾ cup 180 ml heavy cream
Instructions
- Bake the Cake
- Preheat oven to 350°F (175°C).
- Grease a 9×13-inch (23×33 cm) pan.
- In a bowl, whisk flour, baking powder, and salt.
- In another bowl, beat butter and sugar until light and fluffy.
- Add eggs one at a time, then vanilla.
- Alternate adding dry ingredients and milk, mixing until smooth.
- Pour into pan and bake 25–30 minutes.
- Let cool completely.
- Make the Pastry Cream
- Heat milk in a saucepan until steaming (not boiling).
- In a bowl, whisk sugar, egg yolks, and cornstarch.
- Slowly pour warm milk into the egg mixture while whisking.
- Return to heat and cook, stirring constantly, until thick.
- Remove from heat, stir in butter and vanilla.
- Cool completely (cover surface to prevent skin).
- Assemble
- Slice the cooled cake horizontally into two layers.
- Spread the pastry cream evenly over the bottom layer.
- Place the top layer back on.
- Make Ganache
- Heat cream until hot (not boiling).
- Pour over chopped chocolate and let sit 2 minutes.
- Stir until smooth and glossy.
- Finish
- Pour ganache over the cake and spread evenly.
- Refrigerate for at least 2 hours before slicing.
