I got this recipe for authentic tiramisu from my cousin in Italy when I was ten years old. I have been making it for over 25 years and it hasn't failed me yet. People always tell me that it's the best tiramisu they have ever eaten and they always ask for the recipe.
Adapted from cookingwithrosie.blogspot.com
1 - 1-½
1 - 1-½ cups strong espresso, cooled to room temperature
4 large eggs or 5 small/medium eggs, separated
4 to 5
4 to 5 tablespoons sugar (one tablespoon per egg) I use a regular spoon to measure - if you use a measuring spoon it will taste sweeter (personal preference).
16 ounces mascarpone cheese, room temperature
1 (7 to 9 ounces) package Savoiardi or Pavesini (lady fingers) These are known as Löffelbiscuits in Germany.
2 tablespoons unsweetened cocoa powder (or to taste) Again, I use a regular spoon but a measuring spoon will also work.
In a medium bowl, beat egg whites with electric mixture till stiff peaks form but not dry; set aside. In another medium bowl, Beat the egg yolks with sugar until creamy, about 1 minute. If not beaten well, then the filling will have an egg-y taste. Then add mascarpone cheese and mix until there are no more lumps. . Gently fold the egg whites into the mascarpone mixture with a spatula or wooden spoon. Dip the cookies in espresso (you can add a shot of your favourite liquer to the espresso, like rum, amaretto, brandy, Frangelico, marsala, etc.) and lay them into a 9x14 rectangular glass pan (or you may use another container/pan). You can leave 3-4 mm (1/4 inch) or a finger's width between each cookie for the filling, or you can place them close/next to each other so there is no filling between the lady fingers (personal preference). Pour half the mascarpone mixture onto the cookies and spread evenly across the top. Repeat step 4 with the next layer but alternate the cookies perpendicular (or just follow the same pattern as in the first layer) to the ones in the first layer. Refrigerate for over night for best results. If you really must, then refrigerate a minimum of 4 hours before serving but it might still be runny. Sprinkle with cocoa. Makes 12 large pieces or 16 smaller pieces.