Preheat your oven to 200°C (180°C fan).
Prepare the pastry by blending flour, icing sugar, and butter until crumbly, then add egg to form a dough.
Roll out the dough, cut into rounds, and line tartlet tins. Chill for 20 minutes.
Blind bake the tart shells for 10 minutes, remove weights, then bake another 5 minutes until golden. Cool completely.
Heat milk with vanilla until just hot.
Whisk sugar, flour, and egg together, then gradually add the hot milk.
Return to heat and stir until thickened. Chill completely.
Whisk in double cream until smooth and light.
Fill tart shells with crème pâtissière.
Arrange raspberries on top.
Warm the jam with water, strain, and brush over raspberries for a glossy finish.