Start by making the pastry. Take flour, salt, cold butter in a bowl. Rub with your fingers so it forms coarse breadcrumbs like mixture. Add sugar and mix well. Make a well in the center and add in egg and mix well to make a dough. Cover the dough with plastic wrap and chill it for 30 mins.
Preheat oven to 180 Degree C.
Take mini tart pans. Butter it well.
Take the dough from fridge and roll it between two layer of cling wrap. Cut it into small squares bigger than tart pan.
Now place it over the tart pan and layer it evenly. Cut off the excess pastry.
Prick the base of the tart with fork so it doesn't puff up. Put this in freezer for 5 to 10 mins.
Now Bake it for 10 to 15 mins till the tart is crisped up and golden.
Remove it from oven, cool it.
Now remove it from the mould.
Fill a piping bag with lemon curd, pipe it over the tart.