Start by making the lemon cream.
Juice the two lemons and strain the juice through a fine mesh sieve.
Using an electric mixer, beat the egg yolks with the sugar until the mixture is pale and fluffy.
Add the lemon juice and transfer to a small saucepan.

Place over heat and cook, stirring, until the cream starts to thicken.
Add the butter, stir quickly, and remove from heat.
Cover with plastic wrap directly on the surface and let cool completely in the refrigerator.
You can make this a day ahead.

Once the cream is completely cooled, gently fold in the ricotta a little at a time.

Whip the cold heavy cream with an electric mixer, starting slowly. Once it begins to thicken, add the tablespoon of sugar and increase the speed until stiff peaks form.

Take the lemon and ricotta cream and divide it in half.
To one half, gently fold in the whipped cream, mixing from the bottom up to keep it light and airy.

Prepare the lemon syrup.
In a small saucepan, combine water, sugar, and lemon zest. Cook until it starts to boil, then remove from heat and add limoncello and lemon juice.
Remove the lemon zest and let the syrup cool.

Assemble the dessert.
Spread two tablespoons of the lemon whipped cream on the bottom of a baking dish.
Make a first layer of ladyfingers dipped in the lemon syrup, then spread half of the whipped cream mixture on top.
Add a second layer of dipped ladyfingers, a layer of lemon cream, and finish with the remaining whipped cream.

Let rest in the refrigerator for at least 3 to 4 hours. When ready to serve, sprinkle grated lemon zest on top.