Preheat the oven to 180°C.
Combine cake flour, butter, sugar, and salt in a bowl.
Add the egg and knead to make dough.
Let the dough rest in the refrigerator for 30 minutes.
Roll out the dough and lay it in a tart pan.
Prick the dough with a fork, cover with parchment paper, and press down with weights.
Bake for 15 minutes to make the tart shell.
Fill the tart shell with your desired filling (custard, fruit, etc.).
Bake again with the filling for another 10 minutes.
Let it cool, then finish with your favorite toppings.