Ingredients for the Lemon Curd:
2 eggs, 200 ml heavy cream
300 g sugar
60 g cold butter
In a small measuring cup, mix the lemon juice with the sugar, Limoncello and 1/4 cup water until the sugar is dissolved. Set aside.
Place the mascarpone and ricotta cream cheeses, lemon curd and heavy cream in a food processor and process until smooth and a bit fluffy.
To assemble the tiramisu, place half the ladyfingers in the bottom of an 8-inch square baking dish, breaking a few to fit, and dip in the half of the lemon syrup. Top with half of the lemon cream. Repeat the layers, using the remaining ladyfingers, syrup and lemon cream. Cover with plastic wrap and chill at least 2 hours. Before serving, top with the roughly chopped pistache.