*Use any kind of vegetables your family likes to make this quiche. Just cut into bite-sized pieces and steam or sauté until tender but still a little crisp. You can also use leftover veggies from last night’s dinner, or any frozen vegetables prepared according to package directions. If you want to use spinach, just chop it coarsely and add to the mixture without cooking.
Preheat the oven to 350°F (180°C). Grease two 9 in (23 cm) pie plates (disposable aluminum, if you’ll be freezing).
Heat the oil or butter in a large skillet over medium heat. Add the onion and cook, stirring, until quite softened — about 5 minutes. Transfer to a large mixing bowl. Add the cooked veggies, cheese and parsley, and set aside.
In another mixing bowl, whisk the eggs until just mixed. Add the milk, flour, baking powder, salt and pepper, and whisk until combined. Pour into the bowl with the vegetables and stir. Dividing the mixture evenly, pour into the prepared pie plates. Place in the oven and bake until browned and puffed, and a knife inserted into the middle of the quiche comes out clean, 35 to 40 minutes.
Serve one quiche today and let the other one cool to room temperature. Wrap tightly in foil, label and freeze. To reheat, first thaw in the refrigerator, then remove foil before placing in a 350°F (180°C) oven for 15 to 20 minutes, or until heated right through.