1) Preheat the oven to 180°C/ gas mark 4. Whisk together the flours, pecans, cinnamon and salt and set aside.
2) Cream the butters and the 80g of sugar. Add the egg white and continue beating until light and fluffy. Beat in the vanilla essence.
3) On low speed, gradually add the flour mixture and beat until a dough forms. Shape the dough into 7 1/2cm balls, about 1 heaping tbsp each.
4) Place the dough balls 5cm apart on baking sheets lined with greaseproof paper. Bake until lightly browned on the bottom, 10 mins.
5) While the biscuits are still hot, sift icing sugar over the tops. Transfer to a wire rack and cool completely .