Take butter out of fridge to bring to room temperature. Slice eggplant and sweat by sprinkling with salt. Let sit for at least 30 minutes then cube.
Add salt to flour and mix, then cut butter into flour. Add water and then knead until dough forms. Set aside.
Pre-heat oven to 350 degrees and heat oil in large saute pan on medium.
Add eggplant, zucchini, and squash to the pan. Salt and pepper. Cover and let cook for 7-10 minutes, stirring occasionally.
Roll out the pie dough in to a large circle to fit into pie dish. Gently lift dough, place in dish, and trim to fit. With a fork, gently pierce the bottom of the dough in a circle around the base of the pan. Bake in oven for 10 minutes.
Add the rest of the vegetables to the saute pan, cover, and cook for another 10 minutes or until the onions are translucent. Peppers may still be a bit crunchy but they should finish in the oven. Stir occasionally and salt and pepper to taste.
When pie crusts are done, remove from oven and sprinkle half of the feta down for a thin layer. Add vegetables on top filling each pie crust. Sprinkle top with remaining feta.
Bake for 30 minutes.
Serve and enjoy!