Syrup: Begin by brewing 400 ml of strong coffee. Once brewed, dissolve 40 g of sugar into the warm coffee. If using, add 40 ml of coffee liqueur for enhanced flavor. Let the mixture sit until it is warm but not hot.
Cream Mix: In a small bowl, combine 7 g gelatin powder with 50 ml of cold water and let it sit for about 5 minutes. Meanwhile, whip 320 g of whipping cream in another bowl until soft peaks form. In a separate large mixing bowl, beat together 250 g mascarpone cheese and 250 g dulce de leche until smooth and creamy. Gently fold the whipped cream into this mixture until well combined. Finally, stir the softened gelatin into the cream mixture, being careful not to deflate it.
Assembly: Take the ladyfingers, about 20-24 pieces, and quickly soak each side in the prepared coffee syrup. Arrange a layer of soaked ladyfingers at the bottom of your desired serving dish. Spread half of the dulce de leche cream mixture over the ladyfingers. Repeat the process with another layer of soaked ladyfingers followed by the remaining cream mixture. Smooth the top with a spatula and refrigerate for at least 4 hours or even overnight for the best flavor.
Decoration: After chilling, whip 200 g of whipping cream with 100 g of dulce de leche until you achieve a stiff texture. Pipe or spread this whipped cream mixture over the top of the tiramisu. Dust with 2 tbsp cocoa powder and sprinkle ¼ bar of chopped dark chocolate for an elegant finish. Chill until ready to serve.