Melt Butter In Bowl Over Hot Water. Stir In Oil And Keep Mixture Warm. Use It To Brush Inside Of 8X11 Pan. Set Oven To 425 Degrees. Whisk Egg Yolks With Yogurt. Stir In Cheese. Fold In Stiffly Whipped Egg Whites. Cover Bottom Of Pan With 1 Layer Of Dough. Brush With Oil Mixture. Arrange 2Nd Layer Of Pastry On That. Brush With Oil Mixture. Scatter 1 To 2 Tablespoons Of Filling. Repeat Process. Filling Every 2Nd Layer Of Dough With Filling. Brush Top Layer With Oil Mixture And Place In Oven. Lower Heat To 350 Degrees. Bake 45 Minutes Or Until Well Browned. Make Sure The Bottom Is Browning As Well. Allow To Rest For 5-10 Under Foil Wrap. Serve.