Sponge: In a large bowl, dissolve the yeast in lukewarm water and stir in the flour. Allow the mixture to sit until quite bubbly, about 30 minutes.
Mix together the white flour, rye flour and salt in a bowl. Stir 1 cup of this mixture and 1 cup of cold water into the sponge. Mix thoroughly and allow to sit another 30 minutes.
Add the whole-wheat flour, chestnut flour and the olive oil. Knead the dough either by hand or in an electric mixer fitted with a dough hook. Mix until the dough is soft and elastic, about 5 minutes. You may need to add a little more flour if the dough is too wet, but you want a soft, slightly sticky dough. Very soft, moist dough makes the best crust!
Put the dough in a large bowl, cover with a towel and allow it to rest in a warm place until it has doubled in size, about 2 hours. If you are making the dough a day before, put the bowl in the refrigerator and let rise slowly overnight.
To cook the doughboys, preheat a deep-fryer or heavy-bottomed pot, with enough oil to come halfway up the sides of the pot, to 375 degrees F.
Be sure to use a frying thermometer to be accurate. Pull the dough into odd shapes that look like elephant ears, then drop them into the fryer, in batches, and cook until golden brown, about 3 minutes. Flip them over with a chop stick and cook the other side until golden brown, a few more minutes. Repeat the process until all of the dough is used. Arrange them on a serving platter and serve with jam, maple syrup, and powdered sugar. Sit down, get coffee and eat.
Cook's Note: The dough usually made a day before using.