Set the oven to 160 C / 320 F. 20 cm (10 in) tart ring or tart mould with a removable base
Mix the dry ingredients together. Rub in the butter until the mixture resembles bread crumbs. ( I like to do this in the food processor. its quicker and keeps the mixture colder)
Whisk the egg to break it up, weigh it, and add to the pastry, Mixing until it forms a dough. Knead the dough together until smooth, with a little gluten free flour on the bench. You can work this dough, there is no gluten in it. The dough may be a little stickier than the pastry you are used to. Push together and flatten down. Refrigerate until firm ( approx 1 hour) or 15 - 20 minutes in the freezer
Sprinkle the bench with gf flour and roll out the pastry and line a 20 cm ( 10 in) pastry case. Refrigerate until firm.
Heat the oven to 160 C. Line the pastry case with baking paper and fill with rice or baking beans. Do not prick the base or the custard will see]p through Bake for around 10 minutes or until about 1/2 cooked and set around the sides. Empty the paper and beans and bake again for around 8 minutes or until golden. Set aside
Ricotta Filling
Zest the orange and put the zest and maple syrup into a bowl and mix well. Add the ricotta and whisk again. Add the eggs and mix until combinedI like to use a stick blender here to get a beautiful smooth custard. You could also use a food processor to blend till just smooth Pour the custard into the tart case and bake at 160 C for approximately 20-25 minutes or until just set. Baking the tart too long will encourage splitting.