Cake:
Preheat the oven to 175C . With a pastry brush or paper towel, coat 28 4/4 cm" jelly- roll pan with the butter. This will seem like a lot; be very generous. Sprinkle the flour or cocoa over the butter and shake the pan to coat the butter fully. Tap the edge of the pan on a table to knock out the excess flour.
Melt the chocolate in a double boiler or a bowl over a pan of simmering water. Set aside to cool to lukewarm.
Beat the egg whites with a pinch of salt until the whites cling to the beater. Add 50 g of the sugar and beat until the whites form stiff, unwavering peaks.
Cream the butter and the other 50 g of the sugar until the mixture is light and fluffy. Add the melted chocolate and beat in the egg yolks one at a time.
With a rubber spatula, stir about 1/3 of the beaten egg whites into the chocolate mixture, then pour the chocolate mixture over the rest of the whites. Sprinkle the flour lightly on top. Gently fold the mixture together until no white streaks remain.
Pour the batter into the prepared pan, spreading it evenly with a rubber spatula. Bake in the middle of the oven for 15 to 18 minutes, or until the cake shrinks slightly away from the sides of the pan and a knife inserted in the middle comes out clean. It will still be very flat. Loosen the cake from the pan with a sharp knife around the sides and turn it out onto a rack to cool. (Put the rack over the pan and flip the whole thing over to keep the cake from breaking.)
Filling:
In a small heavy saucepan, combine the cream and chocolate and stir over medium heat until the chocolate dissolves. Then reduce the heat to very low and simmer, stirring constantly, until the mixture thickens to the consistency of a pudding. Pour it into a bowl and refrigerate for at least 1 hour.
When the mixture is very cold, pour in the rum and vanilla and beat with a whisk or beater until the filling is smooth and creamy and forms soft peaks when the beater is lifted. Do not over beat or you will get butter. (If this should happen, don't despair; chocolate buttercream makes a perfectly fine filling.)
Cut the cake in half to make two layers, each 22 cm wide. Spread the filling over one layer and set the other layer on top. Smooth out the edges with a spatula. If one of the cake layers should break, use it on the bottom. Refrigerate on a rack for about 1 hour.
Glaze:
In a small heavy saucepan, heat the sugar, water, and chocolate over medium heat, stirring constantly, until the sugar and chocolate are dissolved. Make sure the sugar is fully dissolved or you will get a grainy glaze. Cover the pan and let the glaze cool for about 20 minutes.
Set a jelly-roll pan on a table with one short edge propped up. Put the rack with the cake on something else so that it is suspended level over the pan but offset 5 cm so that you can reach down into the lower pan with a spoon.
Hold the pan with the glaze about 5 cm over the cake and pour the glaze on the cake. Using a large spoon, scoop up the glaze that collects in the jelly-roll pan and put it back on the cake. Keep doing this until the glaze begins to stop flowing smoothly. You should end up with a thick, even layer of glaze on the cake.
Refrigerate the cake until the glaze is firm, 10 to 20 minutes.
Serve by cutting into 35 small equal pieces, 5 in each row across and 7 in each row down. For cutting, use a sharp knife that has been dipped in warm water and wiped off between slices. Keep refrigerated, but for maximum flavor, allow to come to room temperature before serving.
Author's Notes: Serving these will guarantee the success of any endeavor. The name is pronounced, approximately, "rrigo yanshi" (trilled r). This recipe comes from "The Cooking of Vienna's Empire" and is, of course, Hungarian. A friend of mine describes the Hungarians as "the people who taught the Viennese how to bake."
Fine granulated sugar is not the same thing as confectioner's sugar. Regular granulated sugar will work ok for the glaze, just make sure it is fully dissolved. You can avoid lots of chopping by using chocolate Difficulty : Quite difficult. For experienced dessert cooks only. Precision : measure carefully.
