Crust: In a stand mixer, cream the butter and sugar together until light and fluffy. With the motor still running, add 1 ½ tablespoon of egg, the vanilla extract, and then slowly add the flours.Mix until the whole mixture is combined. Drop the pastry into the tart shell and press it into a 14" x 4.5" rectangular or a 9" circular tart pan and evenly press it into the bottom and sides of the pan.Refrigerate the pastry in the tart pan for a minimum of 1 hour and up to overnight.
Curd: Whisk the eggs, ½ cup sugar, and the lime juice in a saucepan over medium heat.Whisk it constantly until it becomes thick enough to coat a spoon, which should take about 8-10 minutes.Transfer the curd mix to a blender and blend on a very low speed, slowly adding small chunks of the 2 tablespoons of unsalted butter a little at a time.Next, transfer the curd to a bowl, cover it, and chill for 2 hours at a minimum.
Preheat your oven to 350F. Bake your chilled tart shell (either blind bake or poke fork holes in it) for 8-10 minutes until it is golden brown.
Next, whisk the mascarpone cream into the chilled lime curd until fully combined.
Pour the filling into the cooked tart shell, and chill for a minimum of 30 minutes.
Top with your favorite fruit and serve.
Take this recipe to the next level by adding a fruit glaze. Simply heat some apple jelly or apricot jam and brush it over the fruit tart with a pastry brush. Pop the glazed tart in the refrigerator for 30 minutes before serving.
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Notes
The curd can be made up to 3 days in advance. However, mix in the mascarpone cream the day of.The crust dough can be made up to 2 days in advance.Decoration: Garnish with whatever is in season. For example, berries, passion fruit, figs, pomegranate.