Mini Boston Cream Cakes with Chocolate Ganache and Creme Patisserie

Mini Boston Cream Cakes with Creme Patisserie and Chocolate Ganache Glaze

Warning: the creme patisserie is the long lead time item here; it has to chill for at least two hours before you can use it. I didn't notice that when I made these, so I had to wait around FOREVER for it to set. DON'T BE ME. Make it ahead.

Cupcakes:

6 tbsp (3/4 stick) butter, cut into pieces

1 1/2 cups flour

1 1/2 tsp baking powder

1/2 cup milk

3 eggs

1 cup sugar

1 tsp vanilla extract

Preheat oven to 350 F. Butter and flour your cupcake tins. This is really important -- I have baked using spray before, and it just does not work the same. Stuff does not come out nearly as nicely. If you can, definitely do it this way. The cupcakes popped right out with hardly any effort on my part at all.

Sift together flour and bp; set aside. In a saucepan, combined milk and butter. The recipe says to do this over "very low heat", in which case I should warn you that it takes a million years. I ended up turning it up -- first to 1 on a numbered stove, then to 3 and finally 5 (since ultimately you need it to boil).

Edit: I ended up making a second batch of cupcakes because I had ganache/cream left over, and definitely go ahead and heat up the milk faster.

Use an electric mixer to whisk the eggs and sugar until fluffy, pale, and thick enough to hold a ribbon on the surface for a few seconds -- about five minutes. Reduce speed, and add the flour slowly. Don't over mix.

Bring the milk stuff to boil. Again -- this can take a long time, and in the meantime the batter will get all weird and spongy; you may need to mix it again to get it back to the right consistency. When the milk boils, add it slowly to the batter and mix until smooth. Add vanilla.

Fill the prepared tins. The recipe says to fill halfway full, but I found that the cupcakes did not rise as much as I expected, and 3/4 full is probably better. I say this as someone who always overfills the cups, this is actually a recipe where it's better to overfill. Instead of running over, this batter rises up in a dome, so you don't have to worry about a mess. Bake for 8 minutes, turn, and bake for another 8.

I was able to transfer the cupcakes out of the pan immediately, using a knife to go around the edges. You may prefer to wait 10 minutes. When the cupcakes cool a bit, you can cut them in half very gently, using a serrated knife.

Creme Patisserie:

4 egg yolks

1/2 cup sugar

1/4 cup cornstarch

pinch of salt

2 cups milk

1 tsp vanilla

Whisk the egg yolks in a bowl; set aside. Combine sugar, cornstarch, and salt in a saucepan, heat over medium; slowly add milk. Cook until mixture thickens, stirring constantly. My recipe suggested this should only take five minutes, but it definitely took longer for me. It will get only slightly thicker, like very watered down glue, but you can see it on your spoon.

Add a third of the milk mixture to the egg yolks while whisking constantly, then add it back and continue to cook it, still whisking constantly, until it comes to a boil and gets really thick. At this point, it is so thick that "boil" is kind of a difficult term. It will make a lot of big thick bubbles that pop grossly, and it is very pale yellow. I found that 5 minutes was about right here.

Take it off the heat, add the vanilla, strain it through a sieve into a heatproof bowl. Cover it with plastic wrap, pressed down onto the surface to keep a skin from forming (note: I did not do this, because I am lazy; the skin can be whisked back into the mixture pretty easily, though). Refrigerate until chilled and firm, anywhere from 2 hours to 2 days.

Ganache:

6 oz. semisweet chocolate, finely chopped (I used mini chocolate chips, which worked well and avoided a lot of extra work)

2/3 cups heavy cream

1 tbsp light corn syrup.

Put the chocolate in a heatproof bowl. Bring cream and corn syrup to simmer in a small saucepan over medium heat, then pour over chocolate. Let stand for a little bit.

Then stir it together slowly until it combines, which make take a little bit. The mixture will get thick and creamy. At this point, you can strain it to get out any remaining chocolate solids (of course I did this, I am anal-retentive about straining things), which leaves it nice and smooth. 

Take your halved cupcakes and put about a spoonful of creme patisserie on the bottom half. For the top half, take a spoonful of ganache and spread it around so the cupcake top is fully covered. Stick them together, et voila!

Caveat: These recipes make about 1/3 more ganache and creme patisserie than cupcakes. I ended up making another half batch of cupcakes to use up the extra. If you don't want to deal with this, you may want to halve or do 2/3 recipes of the former.

ALSO, I would definitely serve these chilled. You can see from the pictures (above: chilled, right: not chilled) that the ones I chilled have a much smoother texture and the creme patisserie is firm enough to hold up without the tops sliding off (which they will definitely try to do). If you are making them for an event, definitely make them ahead and let them sit in the fridge for an hour or so.

Adapted from Martha Stewart's Cupcakes.