Note: This recipe calls for 4 x 4-inch mini tartlet pans (or 1 large tart). For me, it resulted in 3 X 4-inch mini tartlets.
Preheat your oven to 400° F (200° C). Grease your tartlet pan(s).
Roll out your shortcrust pastry to 1/4inch (5mm) thickness and line the tartlet pans, leaving about 1/4inch above the edge to allow for shrinkage.
Brush the bottom of each with the beaten egg, prick with a fork, and blind bake (that means bake just the dough) for 10-12 minutes (for the mini tartlets) or 15-18 minutes (for the large tart). Remove from the oven and reduce the temperature to 375° F (190° C).
Crush the strawberries in a dish and set aside to let juice run out.
Beat the egg yolks and sugar in a heavy bowl until the mixture is pale yellow and the sugar has dissolved. Sift in the flour, a third at a time, beating vigorously after each addition.
Bring the milk to a boil, then pour it gradually onto the flour mixture (whisking continuously). Once the milk is incorporated, add the whole mixture to your saucepan, and reheat it to boiling point, whisking continuously. When it reaches temperature, it will be quite thick. Remove from heat.
Stir in the crushed strawberries. Add to your tartlet shells.
Bake 10-15 minutes. Once cooled, use your remaining strawberries to decorate. Note: I think tarts like this are best eaten cold, so I'd suggest refrigerating at least a couple of hours before serving. Enjoy!