Ingredients
Pastry Cream
- 1 1/2 cups milk
- 4 egg yolks
- 1/4 cup caster (super-fine) sugar
- 1/8 cup flour
- 2 tbsp cornstarch
- 1/2 tsp vanilla extract
Whoopie Cakes
- 1 box vanilla cake mix
- 2 eggs
- 3 1/3 tbsp oil
- 2 3/4 tbsp water
Ganache
- 5 oz dark chocolate
- 2/3 cup heavy cream
To Assemble
- Pastry cream
- Whoopie Cakes
- Ganache
Steps
Pastry Cream
- In a saucepan, add the milk and bring to a boil. Remove from heat and let it cool for a few minutes.
- In a large mixing bowl, add the eggs and sugar and whisk together.
- Add the flour, cornstarch and vanilla and mix to combine.
- Pour in the hot milk and stir to combine.
- Return the mixture to the saucepan over low heat, whisking constantly, while bringing it to a boil.
- Cook until thickened, then remove from heat and transfer mixture to a bowl.
- Put plastic wrap on the surface of the pastry cream to stop it forming a skin, and chill until needed.
Whoopie Cakes
- Preheat the oven to 350 degrees.
- In a mixing bowl, add the cake mix, eggs, oil and water and whisk together.
- Transfer batter to a piping bag fitted with a 1/2-inch round nozzle, and pipe 1 1/2-inch rounds onto a tray.
- Bake for 15 minutes, then leave to cool on a wire rack.
Ganache
- Finely chop the chocolate and place in a large mixing bowl.
- Warm the cream in a saucepan until it comes to a gentle simmer, then pour it over the chocolate and whisk into a smooth, shiny ganache.
To Assemble
- Sandwich the cakes together with piped pastry cream, then spoon ganache over the top.
- Drizzle runnels over the side of the cakes, just like a Boston Cream Pie.
- Leave to set in the fridge for one hour, then serve.
