Preheat the oven to 425 degrees Farenheit and spray a pie plate with non-stick spray.
Take the shredded sweet potatoes and press them into the bottom and sides of the pie plate.
Bake for 25 minutes.
Remove the crust from the oven and lower the oven to 375 degrees Farenheit.
In a separate bowl, mix the eggs, milk, spinach, red peppers, feta, crushed red pepper flakes, and salt and pepper.
Pour into the pre-baked crust. Return to the oven and bake for 25 minutes, or until the eggs are set.
Remove from oven and let cool for at least 10 minutes prior to cutting.
PRO-Tip: To make sure your quiche is flavorful and not soggy, be sure to start with defrosted frozen spinach. Place the spinach in a cheesecloth or clean kitchen towel to wring out any excess moisture.