In a bowl, blend the filling ingredients together and slightly crumble until you get a granola-looking mixture.
Mix the flour, sugar, soda, and a pinch of salt. Beat together the egg, olive oil and water. Make a well in the center of the flour and stir in the liquid. If it seems too thick to handle, add a little water. Turn out onto a floured board and knead for 5 mins. Preheat oven to 120-150°C/250-300°F.
Divide the dough into balls that you can roll out easily. Roll out to about 3 mm thickness. Cut into strips about 6 cm x 20 cm . Lay some filling along the length, in the center of the strip. Dampen one edge of the dough with a wet finger, turn it over the filling to meet the other edge, and crimp the edges well together, making a spine. Take the ends of the rolls and bring them around to join, making a circle. Dampen and crimp them together well.
Arrange on an oiled baking sheet. The spine should be on top, making an attractive ridge, but if you feel that might burst, pale it down on the sheet.
Brush well with beaten egg white and until golden brown, about 45-60 mins.