Place pumpkin into a shallow, heatproof microwave safe dish. Cover and steam for 4-5 minutes until tender. Allow to cool and mash with a for until smooth.
Place the mashed pumpkin into a saucepan and heat it on medium heat for 5 minutes, stirring continuously. (This helps to remove any excess moisture).
Combine the flour, baking soda, sugar, butter and pumpkin pie spice in a food processor and pulse to combine. Place the mixture into a large bowl.
In a separate bowl, combine the pumpkin, yogurt, egg and vanilla and mix well using a whisk.
Add the wet pumpkin mixture to the dry ingredients and stir until the mixture comes together.
Place the pumpkin scone dough onto a pre-lined baking tray and shape it into a disc.
Cut the dough into eight even triangles and place them in the refrigerator while your oven heats up.
Once cooked - combine the powdered sugar and milk to form a thick paste and drizzle over the cooled scones.