Preheat the oven to 400 degrees F. Make almond flour by placing the almonds in a clean, dry, blender or food processor and chopping them until they become powder.
Place the eggs, 1 1/4 cups of the powdered sugar, and the almond flour in a medium-size mixing bowl. Whip with an electric mixer on medium-high speed until creamy and light, about 1 minute. Place the egg whites in a large mixing bowl and whip with an electric mixer on medium speed until foamy. Make a French meringue by adding the remaining powdered sugar, 1 tablespoon at a time, and whipping to stiff but not dry peaks. Do not overwhip. Use a rubber spatula to fold the almond mixture into the French meringue in two additions, being careful not to deflate the batter. Gently fold in the melted butter, then the sifted flour, just until incorporated.
Using an offset spatula, spread about two-thirds of the batter onto a parchment lined sheet pan. Spread the remaining batter onto half of another parchment lined sheet pan. Lightly rest the edge of the spatula on the batter and gently push the excess toward the edges of both baking sheets. Dust the tops of the cake layers with powdered sugar for a nicer crust.
Bake until lightly and evenly browned on top, 6 to 8 minutes. Remove the cake layers from the oven and immediately unmold onto a wire rack to keep the heat of the baking sheet from continuing to bake them. To unmold, invert your cooling rack and place it on top of the cake layer then flip it over. Remove the parchment paper when the layers are completely cool. Set aside until ready to use.
For the Ganache: Pour the heavy cream into a 1-quart heavy-bottomed saucepan, and cook over medium-high heat until bubbles begin to form around the edges. Place the bittersweet chocolate into a medium-sized bowl. Pour the hot cream over the chocolate and let it sit for about 30 seconds to disperse the heat and melt the chocolate. Gently whisk until smooth and homogenous. Set aside until ready to use. Do not refrigerate.
To assemble the cake, cut the large layer in half. You should now have three equally sized pieces of cake. Place 1 layer on a parchment lined sheet pan. Over the top, spread half of the ganache to the edges in an even layer. Cover with another cake layer, then evenly spread the raspberry jam over the top all the way to the edges. Top with the third layer of cake and spread the remaining ganache evenly to the edges. It is very important for this layer to be even as it is the top of the cake. Place the assembled cake in the refrigerator for 1 hour.
To serve, decorate with fresh raspberries.