Combine 5 eggs, kefir, feta cheese, 1/2 cup oil, vegetable seasoning, and baking soda in a bowl.
Preheat oven to 375 degrees F (190 degrees C). Grease a baking pan.
Cover the bottom and sides of the baking pan with 2 sheets phyllo dough. Crinkle 2 more sheets into loose balls; dip balls into the egg mixture until lightly coated. Place into the pan and cover with a flat sheet of phyllo. Repeat crinkling and layering the remaining phyllo, ending with 2 flat sheets.
Mix the remaining egg, yogurt, and 2 tablespoons oil in a small bowl; spread mixture on top of the pie.
Bake in the preheated oven until top turns reddish brown, about 1 hour.