Boston Cream Whoopie Pies

Preheat the oven to 375 degrees F (190 degrees C) and line two baking sheets with parchment paper.

On another piece of parchment paper, trace 2" circles spaced about 2" apart.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large bowl with an electric mixer, beat the butter and sugars together for 2-3 minutes.

Mix in the egg and vanilla until fully combined.

In two additions, alternate folding in the dry ingredients and buttermilk with a rubber spatula.

Transfer the batter to a piping bag with a large round piping tip.

Place your template under a piece of parchment paper on a baking sheet and pipe perpendicular to fill each circle.

Bake the whoopie pies for about 10 minutes or until just barely golden on the edges.

Allow to cool completely before assembling.

In a small saucepan, place the milk over low-medium heat and bring to a simmer or about 190 degrees F (85 degrees C).

Meanwhile, in a medium bowl, vigorously whisk together the egg yolks, granulated sugar, and cornstarch until pale in color and the mixture flows off of the whisk.

Once the milk has reached a simmer, slowly pour half of it into the egg-sugar mixture while simultaneously whisking to temper the eggs. Pour everything back into the saucepan and place over medium heat. Use a rubber spatula to mix constantly as it thickens.

Once the pastry cream is thick and a few big bubbles come to the surface, continue whisking for one more minute, then remove the pan from heat.

Immediately add the butter and vanilla, and use an immersion blender (or rubber spatula) to combine. Pour the pastry cream through a fine mesh sieve into a small bowl to ensure it’s perfectly smooth.

Press plastic wrap up against the surface of the pastry cream to prevent a skin from forming, and place in the fridge to chill overnight or until ready to use.

In a medium bowl, heat the heavy cream in the microwave for about 30 seconds.

Stir in the chocolate until fully melted.

Pair the whoopie pies up, then spread the chocolate ganache on the top ones. Allow to set for a few minutes.

Spread the pastry cream on the bottom ones and gently sandwich with the tops.