Heat a small pan for sauteeing the zucchini and onions over medium heat. Once it is heated add the olive oil and let this heat as well. Add in the onions and zucchini and let them saute for about 5 minutes stirring occasionally.
To this pan, add the chopped spinach and garlic. Saute this for 2 minutes, stirring occasionally. Set this aside to cool.
Preheat the oven to 385 degrees.
On a lightly floured surface roll your pie dough to about 16 inches. Gently add it to your pie pan. Fold over and crimp the edges.
Line the inside with a piece of parchment then fill it with pie weights.
Place in the preheated oven and bake for 10 minutes. Gently remove the parchment and pie weights, then return it to the oven.
Let it bake another 5-8 minutes to par-bake the crust. Remove and set the pie crust aside.
Reduce the heat to 375 degrees on the oven.
Combine the eggs, heavy cream, and milk. Mix well.
Add in the sundried tomatoes, feta, olives, oregano, salt, and pepper. Mix well. Last are the sauteed vegetables. Mix well.
Pour into the pie crust. Place in the oven and bake for about 40 minutes.
Let it cool for about 10 minutes before slicing.