Preparation

1. Preheat the oven to 350°.
2. Grease an 8-inch springform pan.
3. Melt the butter in a large skillet over medium heat.
4. Add the onion, ham, and bread and sautée for about 6 minutes, until the onion is softened and barely beginning to brown.
5. Add the spinach and sautée for two or three more minutes, until the spinach is wilted.
6. Transfer the spinach mixture into the greased pan and spread in an even layer, making sure that the ingredients are well distributed.
7. Sprinkle with salt, pepper and cheese.
8. Whisk the eggs and milk together in a small bowl, then pour over the frittata.
9. Bake for 30 minutes, until puffed and delicately colored.
10. Cool for at least 15 minutes before removing the springform collar and slicing.
11. Serve warm or at room temperature.