Mix half of the all purpose flour and half of the butter in a food processor until coarse crumbs are formed. Add water as needed and mix well until the dough leaves the sides of the bowl. Wrap the dough in a wax paper and refrigerate for 20-30 mins.

Remove the dough from the refrigerator and roll the dough into a flat surface. Using a cookie cutter, cut the dough into desired shapes and transfer them into a baking tray. Freeze the tarts until firm for about 15 mins.

Heat the oven to 425 F. Remove the tarts and prick the bottom of the tarts at one inch intervals with a fork. Cover with foil paper. Bake for 10-15 mins until the crust is set and just beginning to brown. Remove the foil and bake until crust is golden brown. Remove from the oven and allow the tarts to cool completely.

In a pan, mix the remaining flour, sugar, and salt. Add the milk until whisk until smooth. Bring it to a gentle boil for 5-6 mins until the mixture thickens. Remove the pan from the heat.

In a bowl, whisk the egg yolks. Add the milk mixture and mix well. Pour the egg-milk mixture into the pan and whisking constantly, simmer for 2-3 mins until the mixture becomes slightly thick. Remove the pan from heat. Add the remaining butter and vanilla, and mix until the butter is melted. Strain the custard through a fine sieve. Keep it aside to cool.

Once the custard is cooled, carefully add a spoonful of the custard into the prepared tart crust. Top with fresh fruits of your choice. Enjoy the fruit tarts right away or refrigerate and serve.