Step 1

Make the Ladyfingers (if not using store-bought):

Step 2

Preheat oven to 350°F (175°C). Line the bottom of your square pan with parchment paper.

Step 3

Separate egg whites from yolks in two separate bowls.In the bowl with yolks, whisk in ½ of the granulated sugar until light and fluffy.

Step 4

In a clean bowl, whisk the egg whites with a pinch of salt until soft peaks form. Gradually add the remaining sugar while whisking continuously, until stiff peaks form.

Step 5

Gently fold the egg yolk mixture into the egg whites using a spatula. Be careful not to deflate the batter.

Step 6

Sift the flour into the egg mixture and fold it in gently until just combined.Transfer the batter to a piping bag fitted with a plain tip.

Step 7

Pipe ladyfingers onto the prepared baking sheet, leaving a little space between them for spreading.

Step 8

Dust the tops of the ladyfingers generously with powdered sugar.

Step 9

Bake for 10-12 minutes, or until golden brown and firm to the touch.

Step 10

Let the ladyfingers cool completely on a wire rack before assembling the tiramisu.

Step 11

Make the Limoncello Syrup:

Step 12

In a saucepan, combine water, sugar, and limoncello. Heat over medium heat until the sugar dissolves, stirring occasionally. Bring to a simmer for a minute or two, then remove from heat and let cool completely.

Step 13

Make the Mascarpone Cream:

Step 14

In a cold bowl, whip the heavy cream with an electric mixer until stiff peaks form. Gradually add the powdered sugar while beating continuously.

Step 15

In a separate bowl, beat the softened mascarpone cheese until smooth.Gently fold the mascarpone cheese mixture into the whipped cream along with the limoncello and lemon zest. Mix until just combined.

Step 16

Assemble the Tiramisu:

Step 17

In a shallow dish, pour the cooled limoncello syrup.Dip each ladyfinger briefly into the syrup, just to moisten them, not soak.

Step 18

Arrange a single layer of ladyfingers in the bottom of the prepared square pan.

Step 19

Top the ladyfingers with a generous layer of the mascarpone cream.Repeat the layers, ending with a mascarpone cream layer.

Step 20

Dust the top of the tiramisu with unsweetened cocoa powder using a fine-mesh sieve.

Step 21

Refrigerate for at least 4 hours, or ideally overnight, before serving. This allows the ladyfingers to soften and absorb the flavors.