Transfer to prepared pan and trim pastry to fit pan. Use a fork to poke several holes on the bottom of pastry. Use the same fork or your fingers to crimp pastry edges. Place in refrigerator to keep cold.
Heat oil in a large skillet over medium heat. When oil is hot, add diced shallots and cook, stirring occasionally, until tender and translucent, around 5 minutes. Add garlic and cook for an additional minute.
In a large bowl, whisk eggs, milk, salt, and pepper. Set aside.
Pull prepared puff pastry from the fridge and transfer spinach mixture into pastry shell. Pour egg mixture on top, then sprinkle with crumbled feta cheese.
Place pie pan on a rimmed baking sheet. Cover the pan with foil and bake for 20 minutes. Remove the foil and continue baking for another 20 minutes, until the quiche is set and the crust is golden brown.
MEET MARYANNE 👋
I create easy recipes that are mainly vegetarian and vegan. And I have a huge sweet tooth, so dessert is never far behind! Sign up to get recipes delivered to your inbox and get my FREE Guide on Money Saving Tips on Buying Groceries!