Grate the cleaned pumpkin finely and mix it with 1 cup sugar, then leave it for 15 min. to take it in.
Add the oil, cinnamon, walnuts, the rest of the sugar and the yoghurt with the baking soda extinguished in it.
Stir everything with a wooden spoon and add the flour to it.
You're going to obtain a thick cake batter, pour it into a buttered and floured tray that's 13 3/4″ (35 cm) in diameter. Bake in a preheated 356°F (180 °C) oven for 25 min.
Once the cake is fully cooled, sprinkle with powdered sugar.