This cake recipe is adapted from "Martha Stewart Entertaining."
Preheat oven to 350 degrees. Line a 12-inch-round cake pan with parchment paper; spray pan and parchment with nonstick cooking spray with flour; set aside.
Place raisins and whisky in a small bowl; cover and let soak overnight. Melt 14 ounces chocolate with 1/4 cup water in a heatproof bowl set over (but not touching) simmering water. Add butter, a few pieces at a time, stirring until melted. Remove bowl from heat and set aside.
In a separate bowl, beat egg yolks and sugar until thick and creamy. Add yolk mixture to chocolate mixture along with cake flour, ground almonds, raisins, and their soaking liquid; stir to combine.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites and salt until stiff. Gently fold egg whites, one third at a time, into chocolate mixture. Pour into prepared cake pan, spreading evenly with a spatula. Transfer to oven and bake until cake just begins to shrink from sides of the pan, about 25 minutes.
Set a wire rack over a parchment paper-lined baking sheet. Remove cake from oven and let stand in cake pan for 10 minutes before turning out onto a wire rack to cook completely.
In a small saucepan, bring heavy cream to a boil over medium heat. Add remaining 8 ounces chocolate and whisk until smooth. Pour over cooled cake, spreading evenly with a spatula; let stand until set. Garnish with fruits, flowers, and macarons, as desired.