Preheat the oven to 190°C (Gas Mark 5 / 375°F).
In a large bowl, combine the pumpkin with the icing sugar, flour and spices. Mix well.
Divide the mixture onto two large flour tortillas, and spread it around with the back of a spoon (try to go right up to the edges if you can). Sprinkle with granulated sugar.
Use a pizza cutter to cut the tortillas into pieces, and lay the pieces out on a baking tray.
Bake for around 15 minutes, until the tortillas are slightly crispy.