Place all ingredients in bowl of standing mixer except butter and knead until it come together. Add soft butter little by little and knead until smooth and elastic. Cover and let it rise double in size in room temperature. (120 minutes in 27oC).
Sprinkle flour on to working surface and roll out the dough with a rolling pin to obtain a large rectangle 3mm thick.
Cut into rectangles about 1 inch wide by 4 inches long with a crinkle-edged wheel or with a knife. Leave as is, or cut a 2-inch slit down the center of each rectangle to make a hole that will spread open as it cooks. Skip one of the ends of the rectangle through the slit and pull it back, to give a kind of spiral or corkscrew effect to the strips of dough.
Put the bugnes on a baking sheet lined with parchment paper or a silicone mat and let stand for 1 hour.
In a shallow skillet, heat 3 cups of oil to 170oC. Put 4 or 5 strips of dough into the hot oil and cook for about 1 minute on one side, then turn with tongs and continue cooking for another minute. Lift the bugnes from the oil and place on a wire rack while you repeat with the remaining dough.
Then sprinkle with powdered sugar on both sides. Served hot with tea or coffee.