Make shortcrust pastry dough. In a food processor, combine flour with powdered sugar and butter. Pulse until mixture resembles coarse sand.
Whisk egg and slowly add to dough while processor is on. Continue to pulse dough until it comes together. Remove dough from food processor and shape into a ball. Roll out dough between 2 sheets of parchment paper until it's ⅛ inch thick. Lay dough on baking sheet and chill in fridge for 1 hour or until firm.
Remove dough from fridge and peel off top layer of parchment paper. Cut out rounds with 3-inch biscuit cutter for a total of 16 portions. Line 2 ½-inch mini tart shells with dough to create the crust. Poke bottom crust with a fork and return to the fridge for 1 hour or until firm.
Preheat oven to 325 degrees F.
Line tart shells with parchment paper and fill the crusts with baking weights. Bake tart shells for 12 minutes. Remove from oven and remove parchment paper with weights. Return to the oven and continue baking for 8-10 minutes or until shells are golden brown. Remove from oven and let cool completely on a wire rack.
Meanwhile, make kiwi lime curd. Whisk together kiwi juice, egg yolks, egg, sugar, lime juice, and zest in a medium saucepot. Bring to a simmer over medium heat, whisking frequently. Continue to simmer for 15 minutes or until curd is thickened. Remove from heat and add butter, whisking until butter is fully incorporated. Pour curd into a bowl and cover with plastic wrap directly touching the curd. Let cool slightly.
Spoon warm curd into cooled pastry crusts, filling each pastry. Chill kiwi lime tarts in the fridge for 2 hours or until set.
Before serving, top curds with fresh chopped kiwi.
Notes
The shortcrust pastry dough can be prepared the day before and baked the following day.