Whisk flours, baking powder and salt in a bowl. In a measuring cup, whisk oil, yogurt and egg; pour over flour.
Stir to form fairly smooth dough.
On floured surface, knead until smooth, 2 minutes.
Press into disc; wrap and refrigerate for at least 30 minutes.
On floured surface, roll out dough to form a 12-13 inch disc. Fit into 9 inch spring form pan, letting excess hang over edge. Set aside.
Filling
Preheat oven to 375F
In a skillet coated with cooking spray, cook onion, bell pepper and seasoning over medium heat, until fragrant and onion becomes translucent, about 2-3 minutes. Add broccoli and continue cooking for another minute or two.
Add water and balsamic vinegar. Cook until all water has evaporated. Turn off the heat and add chopped spinach and nutmeg. Stir until the spinach is wilted. Set aside to cool.
In a food processor, blend cream cheese and cottage cheese together until smooth. Scrape the sides once or twice during process to make sure all cheese is well incorporated.
Add lemon juice and lemon zest, Dijon mustard and give a quick stir.
Add eggs, one at a time, blending until smooth between each addition. Add the egg whites and take the mixture for a final spin.
Transfer cooked vegetables to a large mixing bowl. Add crumbled feta and creamy cheese mixture. Fold delicately until well combined.
Transfer this mixture into the reserved crust. Immediately put in the oven and lower temperature to 325F.