Set a rack at the middle level of the oven and preheat to 350 degrees.
Use an electric mixer on medium speed, fitted with the paddle attachment to beat together the butter, sugar, brown sugar, espresso powder and almond extract until light, about 2 minutes. Beat in chocolate, then eggs, one at a time, beating well after each addition. Stop to scrape bowl and beater often.
Beat in the cake meal, then almonds.
Scrape the batter into the prepared pan and smooth the top. Bake the cake 30 to 40 minutes, until it is fairly firm in the center, but still somewhat soft in general. Do not overbake or cake will be very dry. Cool the cake up on a rack.
To finish the cake, run the blade of a small knife between the side of the pan and the cake all around to loosen it. Unbuckle the springform side and remove it, but leave the cake on the base.
To make the whipped cream, combine the cream, sugar and vanilla in the bowl of an electric mixer and whip until the cream holds soft peaks. Spread the cream over the top of the cake and sprinkle with the slivered almonds. If you are preparing the cake early in the day, leave it covered at room temperature and whip the cream and refrigerate it. Rewhip the cream if it has separated, spread it on the cake and sprinkle with the almonds right before serving.