1-First Step: Prep your workspace (mise en place) Preheat oven to 375°F (190°C). Grease a 9-inch pie dish with cooking spray. Chop 2 cups spinach, 1/2 cup onion, and 1 cup other veggies. This quick setup, about 5 minutes, ensures everything ready and reduces stress, great for busy schedules.

2-Second Step: Sauté the vegetables Heat a skillet over medium with a touch of oil. Add diced onion and chopped veggies; cook 4-5 minutes until softened. Stir in spinach until wilted, about 2 minutes. Season lightly with salt and pepper. Drain excess liquid to keep your quiche firm, not watery. This step builds flavor in your spinach quiche.

3-Third Step: Whisk the egg mixture In a bowl, whisk 8 egg whites, 1/2 cup milk, 1/4 cup crumbled feta, salt, pepper, and spices until smooth, 1-2 minutes. Fresh egg whites yield fluffier results. For dairy-free, almond milk works seamlessly here.

4-Fourth Step: Assemble the quiche Spread sautéed veggies evenly in the pie dish. Pour egg mixture over top, ensuring even coverage. Sprinkle extra feta if desired. Tap dish gently to release air bubbles for uniform baking.

5-Fifth Step: Bake to perfection Bake 25-30 minutes until center sets and top turns golden. Edges puff slightly. A knife inserted in center should come out clean. Avoid overbaking to prevent dryness.

6-Final Step: Cool and serve Let rest 5 minutes for easy slicing. Serve warm with salad. For low carb quiche fans, pair with avocado. Store leftovers as noted later. Pro tip: Add cooked bacon bits pre-dairy-free for extra savoriness.