My husband had a birthday last week. We celebrated by visiting the Danish island Samsø (photos coming soon!) and enjoying slices of this amazing cake.
When I was in Oregon last month I picked up a few bags of unsalted, shelled pistachios. So when Alan's birthday was approaching, I wanted to make a cake that incorporated them.
I found just what I was looking for in Heidi Swanson's Gateau Surprise Chocolat Pistache. It hit me first because it looked terrific, and after because it originates from Clotilde over at Chocolate & Zucchini. I know how picky the French are about their sweets, so I thought it would be a perfect match for my French husband's palate. Verdict: He loved it!
Although Clotilde baked hers in a round cake tin, I copied Heidi and used a bread tin. It gave the cake a more rustic presentation, I thought, and furthermore it easily withstood the jostling endured on my bicycle as we rode from the ferry to our accommodations.
This is a wonderfully moist cake with subtle flavors. You could easily marble up the chocolate and vanilla layers with the swirl of a knife, but I really loved the separation between the strong chocolate bottom and the soft, perfumy pistachio flavor on top.
A note about pistachio paste. The recipe calls for it, and I have absolutely no clue if it's sold anywhere in Denmark. Therefore, I looked online for ideas and made my own. In the food processor, I mixed 1/3 cup pistachios with 1/3 cup powdered sugar and slowly incorporated a teaspoon of water at a time (about 4 in all) to arrive at a paste consistency. Just play around with it a little being careful to err on the side of less rather than too much water.
Finally, I went ahead and made the accompanying chocolate ganache recipe and applied it to the top, but feel free to skip this step. As much as I love ganache, the cake is just as divine without it.
Gateau Surprise Chocolat Pistache
adapted ever so slightly from 101 Cookbooks and Chocolate and Zucchini
2t baking powder
1t baking soda
2/3c butter, room temperature
1 1/4c sugar
1 1/2c plain yogurt or sour cream
1 1/2t vanilla
2T unsweetened cocoa powder
1/3c chocolate chips
2T pistachio paste (see note above)
1/3c shelled pistachios, chopped
3oz. dark chocolate
1/2c whipping cream
1. Preheat oven to 360F/180C. Grease either a 10" (25cm) round pan or 9x5-inch loaf pan.
2. Prepare the chocolate batter. In a food processor, or with a hand mixer, which is what I used, combine half the sugar and half the butter and mix until fluffy. Add in the eggs, one at a time, and mix between each. Add half the yogurt and all of the vanilla. Mix.
3. In a separate bowl, combine half of the flour, half of the baking powder, half of the baking soda, and all of the cocoa powder. Add this mix to the butter mix and combine well. Pour into the prepared baking pan, gently stir in the chocolate chips, and place in the refrigerator while you make the pistachio batter.
4. Combine the remaining sugar and butter and add the pistachio paste. Mix well. Add the eggs and the yogurt in the same way you did for the chocolate batter.
5. In a separate bowl, combine the remaining flour, baking powder, baking soda and the chopped pistachios. Add this mix to the butter mix and combine well.
6. Remove the cake pan from the refrigerator. Pour pistachio batter on top of chocolate batter and smooth with a spatula. Bake for 40-60 minutes, until a cake tester comes out clean. Don't overcook. Place on the counter to cool for 5 minutes and then remove from the pan to cool on a wire rack.
7. Once cake reaches room temperature, frost with ganache, or not.
8. To make the ganache, place chocolate and cream in a double boiler (or a bowl sitting atop a pan of simmering water). Mix with a spoon until chocolate is melted and the texture is velvety. Remove from heat and let cool approximately 30 minutes before using.