Have you ever had Boston Cream Pie before? Before I made this last weekend, I have never had it but it made me think. Why is it called "pie" when it is actually a cake?
2 c (278 g) cake flour*
2 tsp baking powder
1 1/2 c (298 g) sugar, divided
8 eggs, separated
1 Tbsp lemon juice
6 Tbsp vegetable Oil
2 tsp vanilla
Vanilla Custard (recipe follows)
Chocolate Glaze (recipe follows)
Preheat your oven to 350F. Oil and line three 9" round cake pans, then set aside.
Whisk together cake flour (see note below), baking powder and 1/2 cup (99 g) sugar in a small bowl. Set aside.
In a large bowl, whisk together the yolks, lemon juice, oil and vanilla. Beat on medium-high until slightly lightened, about 5 minutes. Set aside.
Pour the egg whites into a very clean large bowl. Begin beating on medium-low until foamy, then turn the speed up to high and gradually add the remaining 1 cup (198 g) of sugar. Beat until moderately stiff peaks form (when lifting the beater from the bowl, the peaks should droop slightly), being very careful not to whip the whites until they are dry.
After the whites have been whipped, use a rubber spatula to gently fold 1/4 of them into the yolk mixture. Add another 1/4 of the whites and fold to combine. Repeat until all of the whites have been incorporated, then sift in 1/3 of the dry ingredients. Fold gently until few streaks remain, then add another third. Repeat, continuing to fold very gently, until the last addition of dry ingredients has been fully incorporated.
Divide batter evenly between the prepared pans and bake for 15-20 minutes until the cake springs back when pressed lightly in the center. Cool the cakes in their pans on a wire rack for 10 minutes. Remove the cakes from their pans and wrap them in plastic wrap then refrigerate them for at least 4 hours until they are completely cooled.
*If you don't have cake flour, combine 1 3/4 c (248 g) flour and 1/4 c (30 g) cornstarch to substitute.
Vanilla Custard
2 Tbsp cornstarch
2 c (473 ml) milk (author suggests whole, I used skim without any trouble), divided
6 egg yolks
3/4 c (149 g) sugar
2 tsp vanilla
Combine the cornstarch and 1/4 cup (59 ml) of the milk in a large heatproof bowl, whisking until smooth and free of lumps. Whisk in the egg yolks and set aside.
Pour the remaining 1 3/4 cups (414 ml) of milk into a sauce pan and stir in the sugar. Bring to a simmer over medium heat, stirring occasionally to dissolve the sugar and prevent scorching.
When the milk begins to bubble, use a ladle to pour about a cup of it into the yolks, whisking quickly and immediately to temper them. Pour the tempered yolks into the pan with the rest of the milk and cook, whisking constantly, until the custard just begins to boil. Turn the heat down to low and boil gently, whisking constantly, for 1 minute.
Pour the cooked custard into a bowl and whisk in the vanilla (you have to add it last or it will boil off while cooking). Press plastic wrap directly onto the surface of the custard and chill until set and cool, 4-5 hours.
Chocolate Ganache
3/4 cup heavy cream
1/4 cup butter
3/4 cup semi-sweet chocolate morsels
Assembly
Level the three cakes. Put one down on a serving platter, and top with half of the vanilla custard. Spread the filling out to the edges, then add another layer of cake. Top with the remaining custard, spreading, again, to the edge of the cake. Cover with the last round of cake, bottom side up, and pour the chocolate glaze over the top.
This cake was delicious and pretty simple to make even though it took a long time before I was able to eat it. I kept it in the fridge and it was even better super cold!
