Using a stand mixer, mix everything together until it forms into a smooth dough.
Refrigerate the dough for an hour.
Divide the dough into two portions.
Attach pasta roller to the stand mixer.
Pass one portion of the dough through the thickest setting and repeat until the thinnest setting, making sure to dust the dough each time you run it through the pasta roller.
Lay the sheets flat on a well-dusted countertop and spread a thin layer of butter evenly across the dough.
Start rolling the dough from the short end. Once you finish rolling the first sheet, place it over the second sheet and continue rolling until you have one log of dough.
Preheat oven to 450F.
Cut into 12 disks and place them on the tart mold.
Push the dough from the center outwards until it fits the mold.
Pour the egg mixture into the tart pastry and fill all the way to the top.
Bake for 12 minutes or until the pastry is golden brown and the custard iscaramelized.
Let cool for a 5 minutes and transfer to a cooling rack.
Serve while the tart is still flaky and crispy.