8oz225gr semi-sweet chocolate, broken into small pieces
4large eggsat room temperature
2teaspoonspure vanilla extract
1can14oz/400gr dulce de leche
Fleur de Selor coarse sea salt for decorating, if desired
Preheat the oven to 375°F (190°C). Line half sheet baking pan with a parchment paper and spray cooking spray all over the parchment paper and on the sides.
In a medium bowl, whisk together flour, cocoa powder, baking powder and salt. Set aside.
In a mixing bowl with whisk attachment, place eggs, sugar and vanilla extract. Beat on medium high for 5 minutes, or until the mixture is thick, white and tripled in size. (You can also use a handheld electric mixer, but it’ll take slightly longer, about 8 minutes.)
Meanwhile, in a medium heatproof bowl, combine butter and chocolate and melt in double boiler over simmering water. (Or you can melt the chocolate/butter in a microwave at 50% power in 30-60 seconds increments, stirring well after each session.) Remove from heat and cool slightly.
Then using a rubber spatula, gently fold in the melted chocolate mixture into the egg mixture.
Add the flour mixture and gently mix until just combined.
Pour the batter into the prepared baking sheet, spread it evenly and tap a few times to get rid of bubbles. Bake for 10-12 minutes, or until inserted toothpick comes out clean.
Transfer onto a cooling rack to cool for 5 minutes. Then place a wire rack on top of the cake and invert. Remove the baking sheet and peel off the parchment paper. Now place another wire rack on the cake and then invert it again so that the top of the cake is up. Cool completely and then tightly wrap with plastic wrap and freeze for a few hours, or overnight. (It’s easier to handle the cake without breaking it when it’s frozen, as the cake layers are quite fragile.)
To assemble the cake, carefully place the frozen cake on a cutting board. Cut off the edges to even out the cake, and then cut the cake into 3 equal parts.
Spread dulce de leche evenly over each cake layer. Then carefully place each layer on top of each other. Cut the cake into 1.5×2-inch (about 3.5x5cm) pieces.
Right before serving, sprinkle fleur de sel, or coarse sea salt on each cake.