Add the salt to the flour and then rub in the butter until it resembles fine breadcrumbs.
Add the sugar then the eggs and lemon zest and mix to a dough. Knead until smooth and then wrap in cling film and rest in the fridge for an hour.
Preheat the oven to 180C/350F/Gas 4.
Grease a 20cm (8 inch) tart tin with butter or four individual tart tins . Cut about one third of the pastry off and set to one side. This is going to be used for the top. Roll out the remaining pastry to about 5mm (1/8 inch) so that it covers the base and sides of the tart tin. Fill the pie with the jam.
Roll out the remaining pastry and cut into strips about 1 cm (1/2 inch) wide. Arrange in a criss cross pattern across the top of the pie and then place on a baking sheet.
Bake for about 30 minutes until the pastry is cooked and golden. Leave to cool on a wire rack for a few moments as the jam will be very hot. Remove from the tin and serve with cream.