First Step: Preheat the oven to 190°C (375°F, 170°C fan). Line the bottom of a 24 cm (9.5-inch) springform pan with parchment paper, leaving the sides ungreased to help the torte release easily after baking.

Second Step: Pulse the walnuts in a food processor until they resemble coarse breadcrumbs, avoiding overprocessing to maintain texture.

Third Step: Beat the egg whites with a pinch of salt on medium speed until firm peaks form. Gradually add sugar over about 10 minutes until the mixture becomes thick, glossy, and smooth forming a stable meringue base.

Fourth Step: On low speed, add egg yolks one at a time along with the tepid water. Combine evenly without deflating the egg whites.

Fifth Step: Sift together the flour and baking powder. Gently fold the flour mixture alternately with ground walnuts into the batter using a whisk to maintain airiness and light texture.

Sixth Step: Pour the batter into the prepared pan, smooth the surface, then immediately lower the oven temperature to 170°C (325°F) and bake for about 45 minutes. Insert a toothpick to check doneness it should come out clean.

Seventh Step: Cool the sponge in the pan on a wire rack. Loosen edges with a knife and remove the springform ring. For next-day assembly, wrap sponge tightly or refrigerate for up to 3 days. To slice more easily, freeze sponge for 40 minutes before cutting into three equal horizontal layers using a serrated knife.

Eighth Step: Place each layer cut side up on a serving plate and drizzle 5-6 tablespoons of cooled, sweetened coffee evenly over each. Chill layers briefly in the freezer to keep them firm.

Ninth Step: Beat chilled heavy cream, mascarpone, vodka, espresso powder, and powdered sugar beginning at low speed and increasing until thick, creamy, and spreadable. Avoid overbeating to prevent separation.

Final Step: Spread frosting evenly on the first layer. Place the second layer coffee side up, frost it as well, and top with the third layer coffee side down. Cover the entire cake with remaining frosting. Decorate sides with chopped walnuts and dust the top with cocoa powder. Refrigerate assembled torte for at least 4 hours or ideally overnight for flavors to meld.