Pre-heat the oven to 350F.
Grease a 9-inch baking pan with nonstick spray. Then sprinkle two tablespoons of gluten-free all-purpose flour or almond meal flour.
Set the pan on a piece of waxed or parchment paper and trace around it with a pencil. Cut with kitchen scissors inside the traced line on the paper. Fit the cut piece of paper into the pan.
In a large bowl, whisk together the egg yolks and 2/3 cup of the sugar. Whisk until the yolks become pale in color, about 1 minute. Add the vanilla extract, and whisk well to combine. Set aside.
In the bowl of a standard electric mixer fitted with the whisk attachment, beat the egg whites at medium speed for about 1 minute. Sprinkle in the remaining 2 tablespoons of sugar, and continue to beat the egg whites until they are very white, firm and fluffy. The eggs whites will be ready when you turn the bowl upside down and the egg whites don’t fall out.
Add half of the egg whites to the egg yolk mixture and mix to combine.
Add the remaining egg whites over the yolks, and half of the almond flour.
Gently fold them into the yolks.
Add the remaining almond flour and fold until you have a homogeneous batter.
Here you need to be very gentle. Pour the batter into the prepared pan.
Bake the cake for about 40 minutes. The cake will be ready when it is golden brown and when a toothpick is inserted in the center and comes out clean. Let the hot cake cool on a wire rack for 5 minutes, then run a butter knife along the edges of the cake pan.
Place a wire rack over the top of the cake and flip the cake and the pan. Peel away the parchment paper.
Turn the cake right side up and allow to cool completely.
Spread the melted chocolate over the top and add some fresh berries.