In a bowl, whip the heavy cream with an electric mixer. Separate the egg yolks from the whites. Beat the egg whites until stiff peaks form. In another bowl, beat the egg yolks with the sugar using the electric mixer. While mixing, add the mascarpone, lemon juice, and lemon extract.

Gently fold the whipped cream and beaten egg whites into the mascarpone mixture using a spatula, mixing from the bottom up to keep it light and airy.

Once all the ingredients are combined, start assembling the tiramisu. Dip the ladyfingers in a mixture of limoncello, sugar, and water, and arrange a layer in a dish. Spread a layer of the cream mixture on top, then add another layer of dipped ladyfingers. Finish with the remaining cream and top with lemon zest.