Homemade Boston Cream Pie

Mmmm...this is one of my husband's favorites. If you aren't from New England, you may not know Boston Cream Pie, but it is actually a cake. Two layers of yellow cake with a custard filling inside and rich chocolate ganache oozing over the top of it. The recipe varies a lot from place to place, but legend has it that it was invented at the Parker House Hotel in Boston, circa 1855.

Cake:
One recipe Sour Cream Yellow cake baked in a 9" round pan. Bake and cool.

Vanilla Cream filling: (this recipe is adapted from the King Arthur Baking Book)
3 Cups Whole Milk
1/2 Cup Sugar
pinch of salt
2 tsp vanilla extract or 1/3 vanilla bean, split lengthwise
1/4 cup cornstarch
1 Tablespoon all purpose flour
4 large egg yolks
4 tablespoons butter

In a medium saucepan, combine 2 1/2 cups of the milk, sugar, salt, and vanilla bean (if using extract instead, add it last). Bring mixture to a boil over medium heat.

Meanwhile, whisk the cornstarch, flour, egg yolks and remaining milk together in a small bowl.

Whisk a small amount of the hot milk mixture to the egg mixture to temper the eggs, then add a little more (you do this a little at a time so that you don't curdle the egg yolks). After you have added two or three small spoonfuls of the hot mixture, pour the egg mixture into the saucepan with the milk mixure, and bring it back to a boil, stirring constantly. Boil for thirty seconds. It will thicken a lot. Remove from heat. Stir in the butter and vanilla. Top it with some plastic wrap and refrigerate until cooled.

The King Arthur Baking book says to pour the mixture through a fine sieve at this point to get any lumps out, but I didn't find it necessary. Perhaps if you were making pastry cream for napoleons or something very delicate, you would want to do it. The King Arthur book also says to fold in 1 cup of whipped heavy cream (whipped to soft peaks) after the custard is chilled to achieve a lighter cream. I find that the thicker cream is great by itself and it is what I see most often for Boston Cream pie, so I don't add in the whipped cream at the end, I just use the vanilla custard itself.

Chocolate Ganache:
3/4 Cup Heavy Cream
1 Cup chopped Semi-Sweet chocolate bits (you can use chocolate chips)
1 Tablespoon corn syrup
1/2 tsp vanilla extract

In a saucepan, bring the cream and corn syrup just to a boil, being careful not to let it scorch. Remove from heat and stir in the chocolate bits until they are melted and smooth. Stir in the vanilla. Let this glaze cool, stirring occasionally, until it is just warm or room temp.

Assembling the Cake:
Cut the yellow cake in half horizontally. Spoon the custard filling onto the bottom half of the cake until it is almost at the edge. Put the top cake layer on and press down gently until the custard comes to the edge. if it oozes out, scrape the excess off with a knife. Spoon the chocolate ganache over the cake, a little at a time, pushing it to the edges and just over so some of it drips down the sides. Refrigerate until ready to serve.