To make this quiche, start by preheating your oven to 350 F.
Next, prepare the quiche filling. Crack the eggs into a large bowl and add in the cottage cheese. Whisk them together well, or use an immersion blender and blend until fully combined.
Then, wash and chop the zucchini, spinach, and tomato, and add them to the bowl with the eggs, alongside the seasonings (the Italian seasoning, sea salt, and ground black pepper). Mix to fully combine.
Grab a deep, 10-12 inch cast iron skillet (or pie tin, if desired) and add 1 tablespoon of oil to the bottom of it. Use a rubber spatula or brush to fully coat the oil amongst the bottom of the skillet.
Next, prepare the phyllo dough crust. Remove the phyllo dough from the package and layer the sheets, one-by-one, inside of the skillet, being sure to overlap them. Allow the edges to hang over the sides. Don't worry if the sheets rip - it's okay!
Then, pour the egg mixture into the center of the phyllo dough crust.
Fold the edges of the phyllo into the pan - see the video above for an example on how to do this!
Then, sprinkle the feta cheese on top of the quiche (if using).
Transfer the tray to the oven and allow it to bake for 1 hour, or until the center has set. If it needs more time, that's okay! Just keep an eye on the quiche to ensure that the phyllo doesn't burn.
Once it's done, remove the quiche from the oven and allow it to cool.
Cut into slices, then serve and enjoy!