Line the bottom of a 9" or 10" springform pan with parchment. Grease the parchment paper and springform pan edges.
Melt the chocolate baking chips and butter in a bowl over a saucepan with simmering water or over very low heat in a heavy bottomed saucepan, stirring continuously.
Remove from heat before completely melted. Continue to stir to finish melting.
In a small bowl whisk the egg yolks. Add the sour cream, vanilla, rum and hazelnut extract. Whisk until smooth.
Grind the almonds and gluten free flour together in a Vitamix or food processor, by pulsing on and off.
Whisk the egg mixture into the chocolate, and then stir in the flour mixture until smooth.
In a clean, dry stand mixer bowl or in a large bowl using a hand mixer, whip the egg whites on very low speed. Increase speed to medium when small bubbles appear. Shake in the sugar slowly with the mixer on medium high speed until stiff but soft peaks form.
Preheat the oven to 350 degrees.
Gently fold the whipped egg whites into the chocolate mixture, a third of egg whites at a time.
Scrape batter into the prepared greased springform pan. Smooth the batter with a spatula.
Bake on the center rack for 20-35 minutes in the center of the oven. Baking time will depend on the size of the springform or cake pan used. Bake just until the top springs back when pressed gently and a toothpick just barely comes out clean (a few specks on it is better, so you don't overbake it).
Cool completely on a wire rack before slicing carefully into 2 layers. Fill with whipped cream or coconut whipped cream and berries, and spread with Dark Chocolate Ganache over the top. Add decoration of berries and piped whipped cream. Refrigerate until ready to serve. Slice into small pieces. Serves 10-12.
Refrigerate until ready to serve. Slice into small pieces. Serves 10-12. Refrigerate any remaining slices.