For the cake:
1 cup flour (all-purpose)
3/4 tsp baking powder
1/4 tsp salt
4 large eggs
2/3 cup sugar
1 1/4 tsp vanilla

For the syrup:
1/3 cup of sugar
1/2 cup water
2 tbsp coffee liqueur or dark rum
2 tsp instant espresso powder or instant coffee

For the filling:
6 large egg yolks
1/3 cup sugar
1/4 cup coffee liqueur or dark rum
1 tbsp instant espresso powder or instant coffee
1/2 cup heavy cream
1 1/2 cups mascarpone cheese
1 1/2 tsp vanilla extract

For garnish:
Unsweetened cocoa
Chocolate curls

Preheat the oven to 350. Lightly grease the bottom of a 9 inch round cake pan and line it with parchment paper. Lightly grease the paper and sides of the pan and then dust with flour. To make the cake, in a bowl, whisk together the flour, baking powder, and salt until blended. In a large bowl, using a mixer on medium high speed, beat the eggs until pale and thick, about 3 minutes. Add the sugar and vanilla and continue beating until very thick and tripled in volume, about 3 minutes more. Sprinkle the dry ingredients over the wet ingredients and, using a rubber spatula, fold gently until blended.

Pour into the prepared pan and spread evenly. Bake the cake until it springs back when lightly touched, about 30 minutes. Let cool on a rack for 15 minutes. Run a small knife around the inside of the pan to loosen the cake. Invert onto a cooling rack and lift off the pan. Carefully peel off the parchment paper. Let the cake cool completely.

To make the syrup, combine the water and the sugar in a small saucepan and cook over medium heat, stirring frequently, until the sugar dissolves. Bring to a boil and remove from the heat. Stir in the coffee liqueur and espresso powder. Set aside and cool to room temperature.

To make the filling, in the top of a double boiler, whisk together the egg yolks, sugar, coffee liqueur, and espresso powder. Set over barely simmering water and beat with the mixer set on medium speed until very thick, about 6 minutes. Remove the top of the double boiler from the heat and set aside to cool, stirring frequently. Meanwhile, in a bowl, using the mixer on medium high speed, beat the cream until stiff peaks form when the beaters are lifted. When the yolk mixture is cooled to room temperature, add the mascarpone and vanilla. Beat until smooth and well blended. Using the rubber spatula, fold in the whipped cream.

To assemble, cut the cake horizontally into 3 equal layers. Remove the bottom of a nine inch springform pan, close the ring, and set the ring on a flat serving plate. Place 1 cake layer in the springform ring. Generously brush and sprinkle with some of the syrup. Scoop about 1 3/4 cup of the filling onto the layer and spread evenly. Place another cake layer on top of the filling, pressing gently. Generously brush and sprinkle with more of the syrup. Spread about 1 3/4 cups of the filling evenly over this layer. Place the third cake layer on top, pressing gently, then generously brush with syrup. Spread the remaining filling to cover the top. Holding the pan ring and plate together, gently tap against the counter to settle the ingredients. Cover with plastic wrap and refrigerate for at least 6 hours or up to overnight.

To serve, run a thin knife around the inside of the ring to loosen the cake. Unclasp and remove the ring. Garnish with chocolate curls and a dusting of cocoa. Slice and serve. Makes one 9 inch cake, or 12-16 servings.

Note: This dessert is a bit labor intensive, but well worth the effort! After you've made it a couple of times, the process goes much more smoothly and quickly.