Grease a (24cm top/22cm base/3 ½cm deep) tart tin with removable base.

Place one sheet of pastry on a sheet of baking paper. Sprinkle with 1 teaspoon sugar. Top with remaining pastry (offset) and sprinkle with remaining sugar. Roll pastry between two sheets of baking paper until large enough to line tin.

Carefully lift pastry into tin and press into sides; trim edges. Press pastry into fluted sides to raise above rim slightly to allow for shrinkage.

Preheat oven to 180C (fan-forced). Place tin on an oven tray; line tin with baking paper, then fill with baking beans. Bake for 20 minutes then remove beans and paper. Pierce base with a fork. Cook for a further 15 minutes, or until golden. Cool. Reduce heat to 160C (fan-forced).

Place the sour cream and sugar in a large bowl and whisk until smooth. Add eggs, rind, juice and vanilla in a bowl and whisk together until well combined.

Pour mixture into prepared pastry case and bake in oven for about 40 minutes, or until filling is just set. Cool in tin then refrigerate.

Decorate with orange slices and dust with icing sugar. Serve with whipped cream.