Begin by combining 1 cup of lemon curd with ½ cup of freshly squeezed lemon juice in a mixing bowl. If using limoncello, stir in ¼ cup to enhance the flavor. Whisk until smooth and well blended, creating a tangy base.

Grab a shallow dish and pour in the prepared lemon mixture. Dip each ladyfinger briefly in the mixture, about 1-2 seconds per side. Arrange the dipped ladyfingers in a single layer at the bottom of your serving dish.

In a large mixing bowl, combine 16 ounces of mascarpone cheese with ½ cup of powdered sugar. Use an electric mixer on medium speed to blend until smooth and creamy, about 2-3 minutes.

Layer the Lemon Tiramisu by spooning half of the mascarpone mixture over the first layer of dipped ladyfingers. Spread evenly, then repeat with a second layer of dipped ladyfingers and the remaining mascarpone mixture.

Cover with plastic wrap and refrigerate for at least 4 hours, ideally overnight, to let the flavors meld and develop.

Once chilled, dust the top with powdered sugar and optionally garnish with mint leaves or lemon zest. Serve chilled.