How to Make It
In a large bowl, combine the flour with the yogurt, canola oil, baking powder, salt and 1/2 cup of water. Mix with a wooden spoon until a soft dough forms. On a lightly floured work surface, knead the dough until smooth, about 5 minutes. Transfer the dough to a clean bowl, cover with a kitchen towel and let stand at room temperature for 1 hour.
Lightly grease a 10-inch round cake pan. Cut the dough into 4 equal pieces. Working with 1 piece at a time, on a lightly floured work surface and using a lightly floured rolling pin, roll out the dough to a 14-inch round. Transfer to a large rimmed baking sheet and brush the dough with 1/4 cup of the olive oil. Scatter one-fourth of the walnuts on top in an even layer.
Arrange another dough round on top and brush with 1/4 cup of the oil; scatter one-fourth of the nuts on top. Repeat the layering with the remaining pieces of dough, olive oil and walnuts. Roll up tightly into a long log.
Transfer the log to the prepared cake pan, forming a big spiral. Press gently to flatten, then brush with the beaten egg and sprinkle with caraway seeds. Let stand for 20 minutes.
Preheat the oven to 350°. Bake the bread for 50 to 60 minutes, until golden and cooked through. Transfer to a rack to cool. Serve warm or at room temperature.