Pre-heat the oven to 180°C (350°F) and grease a 6 hole muffin pan.
Pour the flour into a large bowl. Chop the butter and then add to the flour. Rub in with your fingers (or use a mixing machine) until you're left with fairly fine crumbs.
Beat the egg in a separate bowl and add to the flour mixture. Stir until everything is combined. If the pastry hasn't pulled together, add a touch of water a little at a time until it does (be careful: you can always add more water but it is harder to correct if you add too much).
Roll out the pastry (you may find it easier to use some baking paper because you do want to get the pastry nice and thin). Cut out hearts (or whatever shape you are using) that are slightly larger than the tin you're putting them in.
Place each pastry cut out in the greased muffin pan and using your fingers, gently push the pastry up the sides to cover the whole area. Pop in the fridge for around 30 minutes to rest a little.
Using a fork, poke holes in the pastry and then bake blind (see note 3) for 10 minutes.
Remove from the oven and fill each one with around 1 tablespoon of jam (you may need more depending on how large your tarts are). Don't fill all the way to the top of the pastry as the jam bubbles up when hot.
Bake for around 10-15 minutes, just until the pastry is starting to nicely brown.
Remove from the oven and either leave them as they are or drizzle a little white chocolate over the top. Eat them still a little warm or serve cold. Enjoy!