Boston cream pie does indeed have its roots in Boston, where it was popularized at the Parker House hotel in the middle of the 19th century. But why pie? Modern baking experts believe that since pies predated cakes in the American kitchen, pie pans were simply more common kitchen equipment than cake pans. Cakes like this one were often baked in pie pans, hence the name.
Our Boston Cream Pie uses a buttery, delicate sponge cake for its base. Traditional recipes rely on a beaten whole egg and egg yolk foam, into which whipped egg whites are incorporated. But the problem is that cakes made this way are often dry and chewy. A hot-milk sponge cake, however, includes some melted butter and warm milk, which makes for a tender, moist cake that even opinionated Bostonians approve of.
PREPARING THE CAKE PAN
1. The trick to getting a piece of parchment that fits the bottom of a cake pan is to trace the outline of the bottom of the pan onto the parchment. When cutting out the outline, cut on the inside of the line so that the round fits snugly inside the pan.
2. Grease the inside of the pan evenly with a thin coat of butter or vegetable shortening.
3. Sprinkle flour in the cake pan, then shake and rotate to coat evenly with the flour; shake out any remaining flour.
4. Fit the trimmed piece of parchment into the pan. The butter or shortening, along with the flour, will help the parchment adhere.
MAKING A FOOLPROOF SPONGE CAKE
1. After whipping the egg whites separately from the yolks and whole eggs, gently layer the whole egg mixture on top of the whites in a large bowl, but do not mix together yet.
2. Gently sift the flour mixture over the egg mixtures using a mesh strainer.
3. Use a large spatula to very gently fold the batter together—be careful not to deflate the batter.
4. Pour the warm milk mixture against one side of the bowl and fold until evenly combined and no streaks of flour remain, about 8 more folds.
AFTER THE CAKE IS BAKED AND LAYERED: GLAZING
1. To glaze a cake with chocolate, simply pour the chocolate glaze on top of the cake and let it flow down the sides. Be sure to set the cake on a wire rack over a parchment-lined baking sheet to catch the excess glaze.
Find this and other great recipes in The America’s Test Kitchen Family Baking Book.