Flourless Layer Cake With Chocolate and Raspberries

Preparation

1. 1. Step 1

      Heat the oven to 375 degrees. Place two oven racks in the two middle positions of the oven. Brush two rimmed 13-by-18-inch sheet pans with 1 tablespoon of oil each. Line the bottom with parchment paper. 

   2. Step 2

      Prepare the cake: To a medium bowl, add the almond flour and potato starch. Whisk, breaking up any lumps, until combined. 

   3. Step 3

      To the bowl of a stand mixer with the whisk attachment, add the eggs and salt. Starting on medium speed, whip the eggs for 1 minute, until the yolks and whites are combined. (Alternatively, use a large bowl with an electric mixer, keeping in mind the whisking time will vary.) Raise the speed to medium-high and whip for 5 minutes, until the mixture has tripled in volume and has a light, butter-yellow color. Add half of the sugar and continue whipping for 1 minute. Add the remaining sugar and whip for another minute. 

   4. Step 4

      For the following 3 minutes, slowly stream in the remaining ¾ cup/177 grams of olive oil while constantly whipping, until fully incorporated. Remove the bowl from the stand mixer. Add the almond flour mixture to the eggs. Using a silicone spatula, with a slow stirring motion, gently fold the two until combined. 

   5. Step 5

      Slowly pour half of the cake batter into each prepared baking pan (about 4½ cups/570 grams each). Starting from the center, use a flexible or offset spatula to spread the batter to reach the sides in an even layer. Bake for about 17 minutes, until golden on top and springy to the touch. A knife should come out clean when inserted in the center. (The cake closest to the heat source will bake a few minutes faster than the other.) Remove from the oven and set aside to cool. 

   6. Step 6

      While the cakes bake, make the chocolate filling: To a 2-quart saucepan, add the sugar, salt and 1 ⅓ cups plus 1 tablespoon/310 grams of water. Cook over high heat, stirring occasionally, if needed, until the sugar has dissolved and the mixture reaches a boil, about 4 minutes. Remove from the heat and add the chocolate. 

   7. Step 7

      Fill a bowl larger than the saucepan with ice. Nest the saucepan in the ice. Using a whisk, stir the chocolate mixture for 6 to 8 minutes, until the chocolate melts, the temperature reaches around 60 degrees and the mixture has a pourable, thin, pudding-like consistency. Remove the chocolate from the ice and set aside. It will continue firming up as it sits. The mixture should ultimately reach a consistency similar to warm custard or pudding, thin enough to stay on top of the cake without completely soaking into it like syrup would. If the mixture thickens all of a sudden, place it back on low heat for a few seconds and whisk. If the mixture becomes thinner, nest it back in the ice and give it a quick whisk. 

   8. Step 8

      Assemble the cake: Working with one cake at a time, use the parchment paper to gently remove each cake from its pan, then cut the cake (still attached to its parchment) in half crosswise using kitchen scissors or a knife. (Since the cakes are gluten-free, they are very delicate and can easily break as you maneuver them. In that case, save the broken cake and piece it together in the second or third layer of the dessert.) 

   9. Step 9

      Carefully flip one of the cakes onto a cutting board. Gently peel the parchment paper from the bottom of the cake. Using a serrated knife, trim off ½ inch around the sides of the cake. Carefully slide the cake onto a rectangular serving board or platter. 

   10. Step 10

       Scoop ½ cup/170 grams of the chocolate filling onto the cake. Using an offset spatula, spread the chocolate in an even layer to the edges of the cake. Add a third of the raspberries on the chocolate in an even layer, tearing each berry in half before placing it all the way to the edges of the cake. Press the berries into the chocolate until flattened. Repeat this cake-chocolate-raspberry layering process two more times. (If any of your cake layers seem to be uneven, stack one thicker portion on top of a thinner portion for more even results.)

   11. Step 11

       Place the last cake layer on top, removing the parchment paper. Dollop all of the remaining chocolate on top of the cake and spread it evenly across the top and down the sides of the cake using an offset spatula or bench scraper. 

   12. Step 12

       Chill the cake for at least 4 hours and up to 3 days before serving chilled. Sprinkle a handful of whole raspberries on top before serving. For clean slices, use a serrated knife, dipped in hot water for a few seconds, then wiped dry before slicing.