1️⃣ Prepare the Lemon Curd:

In a medium saucepan, whisk the eggs and sugar together for a minute or so, until light and glossy. Whisk in the lemon juice, zest, and salt. Heat over medium-low heat while whisking constantly for 3-4 minutes, until the mixture begins to thicken slightly. 🍋
Whisk in the butter 1 tablespoon at a time until it is all melted. Continue to whisk the mixture for 5-6 minutes, until it has thickened enough to coat the back of a spoon. Stir in the vanilla extract. 🥄
Use a silicone spatula or a wooden spoon to run the curd through a fine mesh strainer into a storage container. Lay a piece of plastic wrap over the top and press it down until it touches the entire surface of the curd. This will prevent a film from forming on the curd as it cools. 🌡️
Cover with an airtight lid or another layer of tight plastic wrap and chill in the refrigerator for 2 hours or until completely cooled. ❄️
2️⃣ Prepare the Lemon Syrup:

Combine all the ingredients in a small saucepan and cook over medium heat until the mixture is boiling and all the sugar has dissolved, about 4 minutes. Remove from the heat and cool completely. 🍋
3️⃣ Prepare the Mascarpone Cream:

Whip the cream to soft peaks. Add in the sugar slowly, and whip until stiff peaks. 🥛
Combine the mascarpone cheese and ½ cup of lemon curd until smooth. Fold in the whipped cream, vanilla, and lemon zest until smooth. 🍥
4️⃣ Assemble the Tiramisu:

Dip half of the ladyfingers quickly in the cooled syrup until fully coated and layer on the bottom of a 4-quart baking dish. If you need to cut the cookies to fit in the odd spaces, cut them carefully and fill in the bottom of the pan. 🍪
Layer half of the cream mixture over them and smooth. Top with ½-⅔ cup of lemon curd and smooth. 🍋
Dip and layer the other half of the ladyfingers over the top of the cream until it is fully covered with cookies. 🍪
Spread the remaining cream over the top and smooth out. Top with ½-⅔ cup of lemon curd and smooth. 🍋
Let the tiramisu chill in the refrigerator for at least 2 hours before serving. ❄️