These adorable Boston Cream Pie Cupcakes are miniature versions of the classic non-pie hailing from Beantown. Spongy vanilla cupcakes are split and filled with luscious vanilla pastry cream and finished with rich chocolate ganache to yield sweet morsels perfect for any occasion.
To make the pastry cream: Pour the milk, vanilla extract, and salt into a heavy saucepan and heat over medium-high, bringing the milk just to under a boil, stirring occasionally so the milk doesn’t burn to the bottom of the pan.
Meanwhile, in a mixing bowl whisk together the eggs, sugar and cornstarch.
When the milk is ready, slowly ladle about one-third into the eggs, whisking constantly. Pour the egg mixture back into the hot milk and continue whisking over medium heat until the custard is noticeably thicker, about 5 minutes.
To check the correct thickness of the cream, dip a wooden spoon into the custard, remove it and run your finger across it. It should leave a line where your finger crossed. When the custard is thick enough, remove it from the heat and strain it into a clean bowl.
Let cool for 10 minutes, stirring occasionally. Cut the butter into 1 tablespoon pieces and whisk the butter into the cream, one piece at a time. Cover the bowl with plastic wrap and press the wrap directly onto the surface of the cream. Once the cream is a little cooler, put it into the fridge to finish cooling. Pastry cream will keep in the refrigerator for 5 days.
To make the cupcakes: Preheat oven to 350°F. Brush the muffin pans with softened butter, dust with flour, and tap out the excess. Whisk together the flour, baking powder, and salt. Combine milk and butter in a saucepan and set over low heat until butter melts.
With an electric mixer on high speed, whisk eggs and sugar until fluffy, pale yellow, and thick, about 5 minutes. Reduce speed to medium, and gradually add flour mixture until just mixed.
Bring milk and butter to a boil. With mixer on low speed, add hot milk to batter in a slow, steady stream. Mix until smooth and beat in vanilla.
Divide batter evenly among muffin pans (use a ladle or measuring cup to pour out the batter as it is very liquidy). They will be pretty shallow.
Bake, rotating pans halfway through, until cupcakes are golden and a cake tester comes out clean, about 12 to 15 minutes. Transfer pans to wire racks to cool for 10 minutes. If the cupcakes aren't loose, then run a small knife around the edges of the pans to loosen cupcakes. Turn out cupcakes onto racks and let cool completely.
To assemble: Use a serrated knife to gently split cupcakes in half horizontally. Stir or whisk the chilled pastry cream vigorously to loosen it up. Use a medium cookie scoop (about 1 ½ tablespoons) to distribute pastry cream among the bottom of the cupcake halves. Replace top halves and press down lightly to allow the pastry cream to spread out to the edges.
To make the ganache: Place chocolate in a heatproof bowl. Bring cream to a simmer in a small saucepan over medium-high heat and then pour over chocolate. Let stand, without stirring, for a couple minutes until chocolate begins to melt. Gently stir chocolate into cream until the mixture is completely combined. Spoon about 1 tablespoon ganache over each cupcake.
Buttering and flouring a muffin pan may seem intimidating at first with all the cavities, but it's really quite simple. Here's how to do it:
First use a pastry brush to brush softened butter inside all of the cups (the bottoms and all the way up the sides).
Next, add a small spoonful of flour into each cup. The exact amount doesn't matter, but you won't need a lot.
I recommend doing this next part over the sink to catch all the excess flour. Give the pan a good shake to coat the bottom of the cups in the flour, then tip the pan on its side about 90-degrees and gently tap the side of the pan with your hand to knock the flour down onto one of the inside edges of the muffin cups.
Slowly turn the pan clockwise or counter-clockwise while tapping the pan to keep knocking the flour down until the entire cavity of each cup is dusted.
Flip the muffin pan upside down and knock the excess flour into your sink.
You can easily halve this recipe to make 1 dozen. All the ingredients halve quite easily except for the 3 eggs. For those, beat 1 egg and measure out half the beaten egg. Then add another egg and you'll have 1 ½ eggs for the cupcake batter.Adapted from Martha Stewart’s Cupcakes