For the pastry
1. In a large bowl rub together the flour and butter until the mixture resembles breadcrumbs
2. Add the water, salt, egg yolk and sugar to the mixture and bring into a dough using your hands
3. Knead very lightly (take care or the dough can become tough) until there are no visible lumps of butter
4. Wrap in clingfilm or waxed paper and chill in the fridge for at least two hours
5. Once chilled, preheat your oven to 180C (fan), then roll out the dough on a lightly floured surface until the dough is about the thickness of a £1 coin.
6. Transfer the sheet of pastry and line the tin, gently pressing into the corners. Crinkle up a circle of greaseproof paper and place lightly over the pastry. Place baking beans or dried lentils on top and bake for 15 minutes.
7. After 15 minutes, remove the baking beans and greaseproof paper and continue to bake for another 5-7 minutes, or until the pastry is lightly golden brown.
8. Remove from the oven once baked and leave to cool in the tin.
For the filling:
1. In a large mixing bowl, whisk together the egg yolk and sugar.
2. Bring the milk to the boil in a pan (it must rise to the top of the pan). Once boiled, pour half over the egg yolk sugar mixture and whisk quickly. Then pour this back in the saucepan and over a low heat, stir until it thickens enough to coat the back of a spoon.
3. Strain the mixture over a bowl containing the ruby chocolate chips and then mix together.
4. This is your ganache. Leave the ganache to cool but not set.
5. Line the pastry case with the halved raspberries facing up, until the base is covered. Pour the cooled ganache over the raspberries to fill the case and then place in the fridge to set.
6. Once the ganache has set, decorate using some melted dark chocolate, ruby chocolate and the rest of the halves raspberries.