A few weeks ago, Tina of Wandering Eater talked about an advanced copy of Pierre Hermé new book “Pastries” she received. I didn’t even know that Pierre Hermé was coming out with a new book so, my curiosity spiked, I begged to get a glimpse of it. After failing to get a preview copy from the publisher (hello, popular item!) she kindly emailed me a few recipes from the book and one of them was a “Biscuit à la truffe noire” that looked so amazing that within minutes I was on the phone with the truffle black market to try to secure one of those so-called black diamonds. All in the name of a Pierre Hermé recipe.
Now, as you probably know black truffles are very expensive and even more so this year because of the deep freeze in Europe. Perigord truffles have suffered from the cold temperatures so I settled for one from Provence with the deep aromas of the region. A whiff of it is like traveling without moving. Amazing. Now, for full disclosure I didn’t use the whole amount called for in the recipe. My plan is to make three recipes out of ONE truffle. Yes, I’m cheap that way.
Other than the exorbitant price, this recipe is quite simple. I loved the texture of the truffle sponge with a crusty, sugary exterior and a nice bounce. It’s glazed with a white chocolate “mirror” and finished with thin slices of black truffle. Unusual. Complex. Striking. And it’s even better the next day after the black truffle aromas had the chance to permeate every single crumb of the cake.
Biscuit aux Truffes Noires (Black Truffle Sponge Cake)
- Recipe by Pierre Hermé in “Pastries”
- Serves 8
Black Truffle Sponge Cake
- 1 oz (25g) black truffles
- 1 1/3 cups (270g) superfine sugar
- 1 1/3 cups (150g) all-purpose flour
- 10 tablespoons (135 g) unsalted butter, softened
- 1/2 teaspoon (3g) black truffle oil
- 8 egg whites (235g)
- 7 oz (200g) white chocolate (Valhrona)* (I recommend adding 1 extra ounce of white chocolate here as my glaze was a little too thin)
- 1/4 cup (45g) superfine sugar
- Dash (2g) pectin
- 1/3 cup (80g) heavy cream
- 1/2 cup (110g) still mineral water
- 1 tsp (5g) glucose or light corn syrup
- 1 black truffle
For the Black Truffle sponge:
- Preheat a oven (convection of traditional) to 340’F. Grease a hemispherical mold 6 inches in diameter with butter, sprinkle with sugar and place in the refrigerator.
- In the bowl of a food processor, process the truffles with half the sugar. Transfer to a bowl. Sift the flour and whisk it in the truffle sugar. In a separate bowl, mix the soft butter with the truffle oil until very soft and creamy.
- In the bowl of a Kitchenaid, whip the egg whites into stiff peaks, gradually incorporating the rest of the sugar.
- Pour the truffle-sugar-flour mixture over the whipped egg whites and incorporate the truffle oil butter mixture until you obtain a smooth batter (the mixture will deflate quite a bit but that’s okay).
- Transfer the batter to the prepared mold, place it in the oven, and bake for about 15 minutes. Then wedge a wooden spoon between the oven door and the oven to keep it partially open, bake for 45 minutes more. Unmold the cake and transfer it to a wire rack to cool.
- If the cake rose too much cut the bottom part with a serrated knife to make a perfect dome.
For the vanilla miroir:
- Chop the white chocolate and place it in a bowl. In a saucepan, combine the sugar with the pectin. Bring to a boil with the cream, still mineral water, and glucose. Pour one third over of the mixture over the white chocolate in the bowl, and mix from the center outward until smooth. Repeat twice more. Beat the mixture with a handheld immersion blender (or a regular blender) until the miroir is smooth.
- Pour the mixture over the cooled sponge cake. Slice the truffle on a mandoline into thin slices. Arrange the slices over the cake. Serve.