Rub the butter through the flour until it resembles a breadcrumb texture.
Add a tablespoon of regular caster sugar. Then bring the mixture together by adding fresh orange juice a little at a time until it forms a firm dough.
Wrap. Chill the dough in the fridge for 30 minutes.
Take the pastry out of the fridge 15 minutes before you're ready to roll it out to make the tart case, so it comes back to room temperature and is easier to roll.
To blind bake, line pie tin with the rolled out pastry. Then cover with non-stick baking paper and fill with baking beans. Bake for 15 minutes at 180C.
Remove from the oven and carefully remove the paper and baking beans. Leave to cool.
Heat up the milk and ground rice over medium heat, stirring continuously until it thickens.
Stir in the sugar and butter, before incorporating the eggs. You'll want to whisk those first with a pinch of salt and mix them in quickly - so you don't end up with any bits of scrambled egg.
Add the zest of half an orange and half a teaspoon of ground nutmeg into the thick mixture.
Give it a good stir, then pour the mixture carefully into the tart case.
Top with a few sultanas and dust with the remaining nutmeg.
Bake for around 40 minutes on a low heat, approx 160C. You're aiming for cooked pastry and set filling.
Allow to cool fully before serving.