Preheat the oven to 200°C / 400°F / Gas mark 6.
Prepare a baking tray with greaseproof paper and set aside.
Roll out the pastry on a lightly floured surface to about 0.5cm thick.
Sprinkle a dusting of nutmeg using a fine grater, if possible. Scatter over the cinnamon in pinches.
Roll the pastry a few more times to press in the spices.
Cut out circles to line 6 x 10cm round, deep individual tart tins, with a little overhang.
Sit them on the baking sheet and chill in the fridge for 30 minutes.
Line the tart cases with small pieces of scrunched-up baking parchment, fill with baking beans and bake for 15 minutes until set.
Remove the paper and beans, and bake for a further 10-15 minutes until they are biscuit in colour.
Cool, then trim the edges with a small, sharp knife.
Preheat the oven to 150°C / 300°F / Gas mark 2.
In a large bowl, whisk together the eggs and sugar in a large bowl.
In a saucepan, combine the cream, milk and vanilla and bring to the boil.
Pour onto the egg mixture, whisking as you go, then sieve into a jug.
Spoon the blackberries between the tins, then pour over the custard to fill as much as you can.
Grate over some more nutmeg and bake for 20-30 minutes or when the top is set but the centres wobble slightly.
Cool completely before eating.