1. Preheat oven to 350°F and grease a pie pan with non-fat cooking spray.
2. Heat olive oil in a large pan or skillet over medium heat.
3. Once hot, add the onions and cook for 3 to 5 minutes.
4. After that time, add in the spinach and garlic, and cook for another 3 to 5 minutes, until it's all wilted.
5. While that cooks, whisk eggs, salt, and pepper together in a large bowl.
6. Once fully combined, add in the cheese and the spinach mixture, and stir together completely.
7. Pour the raw quiche into the pie pan and place it in the oven to cook for 30 to 35 minutes, until the egg has fully set.
8. After that time, remove it from the oven and let it cool.
9. Once cool, cut the quiche into 5 equal pie slices, place the pieces in 5 separate containers, zest with lemon, and store in the fridge.
10. To heat up, simply microwave your piece on a plate at low power for 2 minutes, and then 30-second intervals after that until it's warm, and then enjoy!
