Put all the ingredients in a bowl of food processor and pulse gently until they turn into smooth and silky, orange dough. Turn out onto the kitchen counter, divide dough in half and shape into two flat disks. Wrap them in cling film and put in the fridge for minimum 30 minutes (a bit longer would be even better).
If you don't have food processor simply sieve your flour, icing sugar and cinnamon into a large bowl and add cold and cubed butter. Rub the butter and flour mixture together with your fingers until they start looking like breadcrumbs. Add remaining ingredients and mix them in with your hand, kneading gently until you reach smooth and silky, orange dough consistency. Proceed as per instructions above.
After the dough has had time to chill, take it out of the fridge and onto the floured kitchen surface. Roll it out to the thickness of pound coin and cut the cookie shapes using the cutter of your choice. Re-roll the remaining dough and repeat until you've used up all the dough.
Bake your cookies on the baking sheet lined with baking parchment in the oven preheated to 170C/325F/Gas Mark 3 for approx 20 min (keep an eye on them from 15 min on just in case your oven is slightly unpredictable).
Transfer baked cookies onto cooling rack and repeat with the remaining ones. Wait for them to cool and enjoy!
Calories are approximate and per cookie/biscuit.
Make sure you use really dry pumpkin puree for this bake. The less moisture the more crunchy and melt in your mouth final result.