Making crustless spinach quiche is simple if you follow these concise steps:

1. Preheat Oven: Start by preheating your oven to 375°F (190°C).
2. Sauté Onion and Garlic: In a skillet, heat olive oil or butter over medium heat. Sauté the chopped onion until translucent, about 3-4 minutes. Add the minced garlic and cook for another minute until fragrant.
3. Prepare Spinach: If using fresh spinach, add it to the skillet with the onions and garlic. Sauté until wilted, around 2-3 minutes. If you’re using frozen spinach, make sure it’s thawed and well-drained before adding it to the mixture.
4. Whisk Eggs and Milk: In a mixing bowl, whisk together the eggs and milk until well combined. Season the mixture with salt, black pepper, and nutmeg if using.
5. Combine Ingredients: Add the sautéed onion, garlic, and spinach to the egg mixture. Stir in the shredded cheese until evenly distributed.
6. Grease Baking Dish: Lightly grease a pie dish or baking dish with olive oil or butter. You want to ensure the quiche doesn’t stick when it’s done.
7. Pour Mixture: Pour the egg and spinach mixture into the prepared baking dish, evenly spreading it out.
8. Bake: Place the dish in the preheated oven and bake for 35-40 minutes, or until the quiche is set and lightly golden on top.
9. Cool and Serve: Once baked, remove the quiche from the oven and let it cool for a few minutes. Cut into wedges and serve!

Following these steps will lead you to a delectable crustless spinach quiche that’s bound to impress.