For the filling:

Cup of Yum
1. In a medium sauce pan whisk together the 65 grams of sunflower oil with the flour.
2. Heat over medium heat by whisking constantly.
3. Once the flour gets a nice golden color , add the milk slowly.
4. Continue whisking until you have a nice thick cream. Remove from heat. Set aside to cool for a few minutes.
5. Mix in the yogurt, egg, feta and Gruyère cheese.

For the pie:

1. Preheat oven to 210°C/410°F. Lay open the phyllo sheets on your working surface.
2. Grease a 10- inch round pan with a good splash of olive oil.
3. Take one phyllo sheet and lay it flat. Grease with sunflower oil, using a pastry brush. Spread lengthwise a 1cm thick line of the filling. (Leave a 1cm empty space on each end of the phyllo so the filling won't come out when rolling)
4. Start rolling the phyllo gently, towards it's other end.
5. Add the 1st phyllo roll into the outer side of the pan. Press softly so it will fit exactly to the walls of the pan.
6. Continue the same process until you fill the pan. (NOTE: every time you add a new phyllo roll into the pan, make sure to secure it's ending under the previous phyllo roll)
7. Grease with sunflower oil. With a toothpick prick the pie all around so the steam will be able to come out while baking and not the filling.
8. Bake for 10 minutes at 210°C/410°F.
9. Reduce heat to 180°C/356°F and bake for another 20-30 minutes.
10. Shake the pan to make sure the pie is cooked at the bottom (shouldn't stick to the pan).