Baumkuchen (Daring Bakers' Challenge)

I got very excited when I saw January's Daring Bakers' Challenge. So excited, in fact, that I promptly dropped the rest of my plans for the weekend, marched to the grocery store to buy almonds, and began baking. This month's challenge was baumkuchen - a traditional cake throughout Europe that has also become very popular in Japan. The name translates to "tree cake" in German. Usually, the cake is ring-shaped, so the layers look like tree rings. Unfortunately, getting this ring-shaped layering requires some specialized equipment, so my baumkuchen has horizontal layers.

The January 2014 Daring Bakers' challenge was hosted by Francijn of "Koken in de Brouwerij". She challenged us all to bake layered cakes in the tradition of Baumkuchen (tree cake) and Schichttorte (layered cake).

I had baumkuchen for the first time when I was in Japan. It's quite popular there. I was not really impressed with the cake flavor - it was dry and basically sponged up all moisture in my mouth when I ate it. It looked super cool though, so I was very eager to try making it for myself. Mr. Buttercream, however, was dubious.

Mr. Buttercream: What are you making?

Me: Baumkuchen. Remember - that cake we had in Japan?

Mr. Buttercream: The cake that looked like layers of the earth? It looked like...strata?

Me: Yep.

Mr. Buttercream: Oh....uh...I didn't like that cake very much.

Me: Me neither, but I'm sure this will be tastier than the grocery store cake we had in Japan.

Mr. Buttercream: Ok...

This totally does look like layers of rock that have slowly accumulated over
hundreds of years. Baking this cake took almost as long...

This is a very time-consuming cake. Each layer is spread and baked separately for about two minutes. After the batter was mixed up, it took about an hour to finish baking the cake, and I had to monitor the cake the entire time to ensure the thin layers didn't burn (you can see I wasn't totally successful in this regard on the top layer). I highly recommend turning on a TV show or movie that you can partially watch while the cake bakes.

Marzipan flowers.

Mr. Buttercream's skepticism about this cake wore off once he had a bite. We both agreed that it was a little on the dry side, but still tasty - especially when accompanied by tea or coffee. It was also coated in chocolate and topped with little marzipan flowers, which made it extra delicious. I was actually a little disappointed with the almond flavor - it was a bit lost in the cake itself. If I ever make this again, I'd probably try adding a bit of almond extract to the chocolate glaze.

Baumkuchen
Adapted from Global Table Adventure.  Makes a 6" round cake.

Ingredients for Almond Paste
3.5 ounces blanched almonds
3.5 ounces powdered sugar
½ teaspoon almond extract
1 egg white

Ingredients for Cake
½ cup cake flour
6 tablespoons cornstarch
6 ounces almond paste
2 tablespoons milk
6 tablespoons butter (softened)
½ cup sugar
5 eggs (separated)
1 teaspoon vanilla extract
~3 tablespoons apricot jam

Ingredients for Apricot/Chocolate Glaze
~3 tablespoons apricot jam
6 ounces chocolate chips
6 tablespoons butter
2 tablespoons water
2 teaspoons vanilla extract
2 tablespoons light corn syrup

Method

1. To make the almond paste, place the almonds and powdered sugar in a food processor. Grind the mixture until the almonds are very fine (they should be almost powdery).
2. Add the vanilla extract and grind the mixture to combine. Slowly (teaspoon by teaspoon) add the egg white, grinding to combine. Add just enough for the mixture to come together (for me, this was about ⅔ of the egg white). If you add too much egg white and the mixture is sticky, just add some more powdered sugar.
3. Gather the almond paste into a ball. Use immediately or wrap in plastic wrap and store in the refrigerator.
4. To make the cake, line a 6" round cake pan with parchment paper. Grease the sides with oil. Make sure your cake pan has high sides - I recommend 3" sides. I actually used a springform pan since mine had higher sides.
5. Sift together the cake flour and cornstarch in a small bowl. Set aside.
6. Place 6 ounces of the almond paste (which should be almost all of it) into a stand mixer fitted with a paddle attachment.
7. Begin to mix. Add the milk slowly and continue mixing until combined. 
8. Next, add the softened butter and mix until fluffy. Add the sugar in a slow stream while continuing to mix. Finally, add the 5 egg yolks and vanilla extract.
9. In three additions, add the flour/cornstarch mixture. Make sure to scrape down the sides of the bowl occasionally. Mix until combined.
10. Place your egg whites in a medium bowl. Beat on high until the egg whites are stiff but not dry. Carefully, fold the egg whites into the batter, trying to keep as much of the air from the whites as possible.
11. Set your oven to broil. I set mine to broil on high and moved the oven rack to the middle of the oven. Your goal is to get an even brown on the top of the cake.
12. Give the oven a couple minutes to heat up while you prepare the apricot jam. Place the jam in a microwave-safe bowl. Heat the jam for 20-30 seconds, or until it is a bit more liquid-y.
13. Pour the jam through a strainer to get any apricot chunks out. Set aside.
14. Spoon three heaping tablespoons of batter into your cake pan. Spread to evenly coat the bottom using a pastry brush. You want the bottom completely covered, but you don't want each layer to be too thick.
15. Place the cake in the over for about 2 minutes. Turn on the oven light and watch it the first couple times - you want the top to get nice and brown but not burnt. Careful here - if you forget about the cake you could very easily ruin it. Remove the cake from the oven.
16. Repeat steps 14 and 15 until you run out of batter, or run out of room in your cake pan (I was at the very top of a 3" tall pan). Every third layer, spread a thin layer of apricot jam on the cake before spreading on the next layer of batter. Try to keep the layers completely level throughout this process.
17. Remove the cake from the oven and place on a wire rack. After 10 minutes, run a knife around the edges and remove from the pan. Allow to cool completely. Wrap in plastic wrap and store in the refrigerator overnight.
18. Remove the chunks of apricot from your apricot jam as you did in step 12. Using a pastry brush, brush apricot jam on top of and on the sides of your cake. Return it to the refrigerator to set.
19. To make the chocolate glaze, place the chocolate chips in a microwave-safe bowl.
20. In a small saucepan, melt the butter over low heat. Add the water, vanilla, and corn syrup and allow to combine.
21. Pour the butter mixture over the chocolate chips. Stir until the chips are melted. If they're not completely melted, or if you want a thinner consistency, place the glaze in the microwave for ~10 seconds.
22. Set your cake on a wire rack over a bowl. Pour the glaze over your cake, trying to get the sides covered. Allow the chocolate to set.