I didn't have time to make the crust from scratch so I grabbed the frozen pie crust from trader joe's! I used this ceramic quiche dish, sprayed it with non stick spray and placed the dough in the dish.
Don't worry if the dough rips a little you can just fix it with your fingers. Place parchment paper on top of the crust and blind bake with pie weights or dried beans at 350 for 20 minutes. Then, remove parchment paper and bake crust again for 10-15 or until golden brown.
While the crust was baking I sliced one medium onion and placed it in a pan with olive oil and a small pat of butter on low heat (very important that heat is low!). Keep pan covered and stir every 3-5 minutes until the onions are perfectly golden brown. Onions will take about 30 minutes to caramelize and add a little sweet component to the dish!
I used 1 bag of frozen spinach, thawed. Once thawed, squeeze all water out of spinach to make sure it doesn't release any moisture into your quiche. Once crust has been pre-baked, take half of the grated cheese and spread on bottom of quiche. Then add spinach, onions and remaining cheese on top.
For Wet Ingredients
Whisk eggs, milk, heavy cream, salt and pepper together in bowl until blended together. Then pour on top of filling.
Bake quiche at 350 for 30-40 minutes or until quiche is set. Let quiche cool almost to room temperature before serving. Can be served cold or at room temperature.