Place the chocolate in the top of a double boiler or in a bowl set over a pot of simmering water, and stir until melted. Remove from the heat and cool to room temperature.
In the top of a double boiler or in a bowl set over a pot of simmering water, beat the egg yolks and 3 tablespoons of sugar until pale yellow and frothy. Add 1/2 cup of the wine and whip until thick, being careful not to let the mixture boil. Remove from the heat and fold in the chocolate. Cool to room temperature.
In a medium bowl, beat the egg whites until stiff peaks form, and fold into the cooled custard mixture.
In a bowl, combine the coffee, ricotta, and 2 tablespoons sugar and set aside.
In a separate bowl, whip the cream until soft peaks form. Add the remaining teaspoon of sugar and whip until stiff peaks form.
Dip the ladyfingers into the remaining 3/4 cup of dessert wine and arrange them in the bottom of a square 9-inch baking dish. Cover with half of the ricotta, half of the custard, and half of the whipped cream. Repeat with the remaining ingredients, ending with whipped cream on top. Cover with plastic wrap and refrigerate until set, at least 3 hours.
To serve, sift the cocoa powder evenly over the top and decorate with the chocolate coffee beans. Cut into equal pieces and serve.
In the top of a double boiler set over simmering water, melt the chocolate, stirring until smooth.
Remove from the heat and let cool and thicken slightly.
In batches, drop the beans into the melted chocolate, coating completely on all sides. Remove and place on a baking sheet lined with waxed paper. Let dry completely.
Store in an airtight container at room temperature.