Preheat oven to 320F
Put the sugar and the mandarin peel into the food processor and process until the peel is very fine and the sugar begins to turn orange.
Add the softened butter to the sugar and process till well mixed and smooth. (1 minute). Scrap down the sides and pulse to combine.
Add the flour and almond meal and mix until just pulling together into a ball.
Tip out onto a work surface and bring the dough together very gently and put onto a baking paper lined tray and cover with another piece of baking paper. Roll out to approximately 1 cm / ¼ in the put into the fridge.
Rest approx 30 min or till firm
Cut the biscuits and put onto a lined flat baking tray. Sprinkle with a little fine sugar if you like. chill again if they have softened.
Bake for approx 15- 20 minutes depending how hot your oven is. Touch lightly in the centre and they should be reasonably firm.
Use the scraps up. Push them together gently. Roll out again and cut into rounds sprinkling with a little sugar