01 - Preheat oven to 350°F. Grease a 9-inch pie dish or baking dish with cooking spray or butter.
02 - In a large skillet over medium heat, sauté the diced onion in a bit of oil until translucent, about 3-4 minutes. Add the chopped spinach and cook until wilted. Remove from heat and set aside.
03 - In a large mixing bowl, whisk together the eggs, milk, cottage cheese, salt, pepper, and nutmeg until well combined. Stir in the shredded cheese and fresh herbs if using.
04 - Add the cooked spinach and onion mixture to the egg mixture. Mix thoroughly to distribute all ingredients evenly.
05 - Pour the mixture into the prepared baking dish. Use a spatula to smooth the top surface evenly.
06 - Bake for 30-35 minutes, or until the quiche is completely set in the center and the top is lightly golden brown. A knife inserted in the center should come out clean.
07 - Allow the quiche to cool for 5-10 minutes before slicing. This helps the quiche set properly for cleaner serving.