Step 1 Place the pumpkin in a steamer set over a saucepan of simmering water and steam for 15 minutes or until very tender. Drain on paper towel to remove excess moisture. Transfer to a food processor and process until very smooth. Step 2 Preheat the oven to 190C/170C fan forced. Lightly grease 16 holes of 24 standard doughnut pans. Step 3 Place 250g (1 cup) of the pumpkin puree in a bowl. Add the eggs, sugar, oil, cinnamon and stevia and use a balloon whisk to whisk together until smooth. Fold in the flour until well combined. Carefully spoon or pipe the mixture into the prepared pans. Bake for 10 minutes or until a skewer inserted into the centre comes out clean. Cool doughnuts in the pans for 5 minutes, then turn onto a wire rack for a further 5 minutes to cool slightly. Step 4 Meanwhile, for the cinnamon sugar, place the sugar and cinnamon in a large sealable plastic bag and shake the bag to combine. Step 5 Place 6 of the warm doughnuts into the cinnamon sugar mixture and gently shake to coat. Repeat with the remaining doughnuts and cinnamon sugar mixture. Serve immediately.