Fresh spinach is best for flavor, but frozen works if well drained., Cooling before slicing helps achieve neat slices., Try sautéing spinach with garlic to enhance flavor., Experiment with different cheeses like feta, goat cheese, or pepper jack., Leftover quiche keeps well in airtight container in the fridge for up to three days., Serve with garden salad, whole-grain toast, salsa, or fresh herbs for extra flavor., Variations include adding bell peppers, mushrooms, zucchini, fresh herbs (basil, dill, parsley), jalapeños or red pepper flakes for heat, or cooked bacon, ham, sausage for added protein., This quiche is naturally gluten-free due to being crustless., For reheating, use oven (350°F for 10-15 minutes slices, 20-30 minutes whole) or microwave in short bursts; frozen quiche can be reheated after thawing or from frozen in oven at 325°F., Do not leave quiche out at room temperature more than 2 hours for safety. Heat to 165°F internally when reheating.