Preheat the oven to 190°C / 170°C fan / gas mark 5.
Add the flour and icing sugar to a large bowl and stir together.
Rub in the chilled dairy-free baking block with your fingertips until the mixture looks like fine breadcrumbs.
Add 2 tablespoons of cold water and mix with a knife until the dough starts to come together. Add the extra tablespoon only if needed.
Bring the dough together gently with your hands, then wrap and chill for 15 minutes if you have time.
Lightly flour the work surface and roll out the pastry to around 3 mm thick.
Cut out 12 circles and gently press them into a 12-hole tart tin.
Spoon about 1 teaspoon of jam into each pastry case.
Bake for 12–15 minutes until the pastry is lightly golden.
Leave the tarts to cool in the tin for a few minutes before transferring to a wire rack.