In a food processor, add in the pie crust ingredients plus ½ cup of powdered sugar and pulse until a dough has formed. Slowly drizzle in the water while pulsing until it becomes a meal-like texture.
Transfer the dough to a clean surface and roll it out until it is about 1/8” thick. Form it into a 2” inch deep 8” round tart pan. Trim off any excess.
Bake in the oven at 400° for 12-15 minutes or until lightly browned and cooked. Let it cool.
In a large metal bowl over a medium size pot of boiling water, whisk together the eggs, egg yolks, ¼ cup of sugar, zest of ½ lemon, and juice of 1 lemon until it becomes very thick, like a custard, which is about 2 to 4 minutes. Be sure to whisk constantly. Remove the bowl and whisk in the butter until it has melted. Cool the mixture in the refrigerator until completely cooled.
In a standing mixture with the whip attachment on high speed, mix the mascarpone and cream cheese until light and fluffy, which takes about 5 to 7 minutes, and then add in the remaining lemon zest, lemon juice, and powdered sugar. Mix until combined, and then fold in the chilled lemon curd.
Pour the mixture into the cooked pie shell and cool overnight in the refrigerator or until it firms up. Garnish with berries and serve!
Notes
Make-Ahead: You can make this up to 1 day ahead of time.How to Store: Cover the Lemon Tart and keep it in the refrigerator for up to 4 days. You can freeze this covered for up to 3 months. Thaw it in the refrigerator for 1 day before slicing and serving.Add 1/4 cup of sugar to the curd if you like sweeter tarts.