1. Preheat the oven to 375 F and grease the pie plate with butter or non-stick cooking spray and press the store-bought pie crust or homemade pie crust into the bottom of the pie plate. Prick the pie crust with a fork a few times.
2. Heat the olive oil in a skillet on the stove over medium heat, for 1 minute. Add the onion and sauté for 3-5 minutes, or until the onion turns translucent. Add the minced garlic and sauté for an additional minute, before adding the spinach to the skillet and stirring just until wilted. Remove the skillet from heat.
3. Scatter 1/4 cup of the mozzarella cheese on the bottom of the pie crust. In a large mixing bowl, whisk together the eggs and cream. Add the drained salmon, skillet spinach mixture, remaining mozzarella, red pepper flakes, salt and pepper and stir to combine. Pour the mixture into the pie crust, and place in the oven for 50-55 minutes, or until the quiche no longer jiggles when you give it a slight shake.* Remove and allow the quiche to cool for 5-10 minutes before slicing and serving with a sprinkle of fresh dill.

Leftover quiche can be kept in an airtight container, for up to 4 days.