Mix flour with little baking powder and little salt. Add the butter to the mix till the mixture resembles fine breadcrumbs.
Add sugar to the mixture and add cold water just enough to make dough. Make small dough balls and set aside.
In the meanwhile, grease the tart tins with little butter.
Press the dough balls into each of the tins and add about half a teaspoon of jam at the center. You can add any shapes of your choice eg. Stars cut out from the dough etc. on top of the jam, to avoid it spreading too much.