Pulse flour, powdered sugar, and salt in a food processor. Add cold butter and pulse until crumbly. Add egg yolk and pulse until dough just comes together, adding ice water if dry.

Form dough into a disk, wrap in plastic, and chill for 1 hour.

Preheat oven to 350°F (175°C). Roll out dough and press into 4 mini tart pans. Prick bottoms and freeze for 15 minutes.

Line tart shells with parchment, fill with pie weights, and blind bake for 15 minutes. Remove weights and bake another 10-15 minutes until golden brown. Cool completely.

Lower oven to 300°F (150°C). In a saucepan, heat cream and vanilla bean to a simmer. Remove from heat and steep for 15 minutes.

Whisk egg yolks, 1/4 cup sugar, and a pinch of salt. Slowly temper hot cream into the yolk mixture while whisking constantly.

Pour custard filling into the baked tart shells. Bake for 25-35 minutes until the edges are set but the center still jiggles slightly.

Cool tarts to room temperature, then refrigerate for at least 4 hours until fully firm.

Before serving, sprinkle 1 tablespoon of sugar evenly over each tart. Melt and caramelize the sugar using a kitchen torch. Garnish with a mint leaf.