01 - Preheat the oven to 180°C (350°F). Grease a tart pan and set aside.
02 - In a mixing bowl, combine flour, softened butter, powdered sugar, egg yolk, vanilla extract, and salt. Mix until the dough forms a ball.
03 - Press the dough into the bottom and up the sides of the prepared tart pan. Prick the base with a fork to prevent bubbling.
04 - Bake the crust in the preheated oven for 15-20 minutes or until lightly golden. Remove from the oven and let it cool.
05 - In a separate bowl, mix the summer fruits with granulated sugar, cornstarch, and lemon juice. Gently toss to combine.
06 - Pour the fruit mixture over the cooled crust, spreading it evenly.
07 - Return the tart to the oven and bake for an additional 10-15 minutes until the fruit is bubbly.
08 - Allow the tart to cool completely before dusting with powdered sugar and garnishing with fresh mint leaves.