Years ago my Tutu "Hawaiian for Grandmother" had made something similar to a Spinach Frittata when I spent part of the summer visiting them in Hawaii probably after a long day of playing at the beach or out shopping for school clothes. I loved how comforting the Frittata was and similar to Quiche minus the crust. It still evokes wonderful memories of my time with my Grandparents when I make this.
Now that I'm older I love the simplicity of this Spinach Fontina Frittata. It's easy enough to make for the family before they head off to work or school, but hearty enough for a simple dinner. I will sometimes add about a 1/4 lb of ground chorizo to the onions, which the boys prefer, and perfect for those protein lovers in your life.
I love that it's all made in one skillet, and then baked in the oven keeping the dishes to a minimum.. It's perfect for breakfast, lunch, or dinner, and a great way to use up leftover bit's and pieces of stuff from the fridge. I'm sure your family will love it as much as mine.