1. Cream the butter, sugar and salt in a mixer or by hand using a wooden spoon.
2. When pale and fluffy add the rice flour and plain flour and mix well until it is all combined.
3. Steep the saffron in warm milk for a few minutes before adding to the dough and mixing well.
4. Lay out on a surface and bring the dough together.
5. Roll it out into a sausage shape (or any shape you like) about 2 inches in diameter. You can stamp/cut out your shapes after it is chilled.
6. Wrap in cling film and place in the fridge to set for a few hours.
7. Preheat the oven to 160°C.
8. Once the shortbread has set remove from the fridge and remove the cling film.
9. Cut into ½ cm slices or roll and cut using a cookie cutter, lay on a baking sheet and bake in the oven for 20 - 30 minutes or until slightly golden but still pale in colour. Keep an eye on them as they change colour quickly at the end.
10. Remove from the oven and allow to cool on a wire rack.