Makes approximately 40 puffs
1/2 cup warm water
Mix the warm water and yeast in mixing bowl of an electric mixer. Let stand until foamy, about 10 minutes.
In separate bowl, mix 1/2 cup of chestnut flour, the icing sugar and cinnamon; set aside.
In the mixing bowl, add the remaining 3/4 chestnut flour, all purpose flour, granulated sugar, butter, egg, and salt. Beat at medium speed until the dough is smooth and elastic, about 5 minutes. Place the dough in an oiled bowl, cover with plastic wrap, and let rest for 45 minutes.
Heat about 7cm (3 inches) of oil in a heavy pot over medium-high heat.
Divide the dough in half. On a lightly floured surface, roll one piece of dough to 3mm (1/8-inch) thick. Cut rounds using a floured 38mm (1-1/2 inch) round cutter.
Fry the rounds, about 10 at a time, turning once until puffed golden, 30 to 45 seconds. Drain on a paper towel. Dust with the reserved chestnut-sugar mixture and serve warm or a room temperature.