Preheat the oven to 350°F (175°C).

In a bowl, combine flour and sugar. Cut in butter until mixture resembles coarse crumbs. Add egg yolk and cold water, mixing until a dough forms.

Roll out the dough and fit it into a tart pan. Prick the bottom with a fork and bake for 15 minutes until lightly golden.

In a saucepan, whisk together milk, sugar, cornstarch, and egg yolks. Cook over medium heat until thickened, stirring constantly. Remove from heat and stir in vanilla extract.

Pour the custard into the cooled tart shell and let it cool.

Once cooled, arrange the mixed fruits on top of the custard.

Heat apricot jam in a small saucepan until melted and brush it over the fruits for a glaze.