Leave the bread in an open, shallow container for several hours or up to 2 days, so that it will harden and become stale.
Preheat oven to 375 F.
In a skillet, heat olive oil. Add garlic and chile. Saute for 1 minute. Add spinach and a pinch of salt. Cook until spinach is wilted.
Combine the grated cheeses together and mix well.
In a large bowl, whisk eggs well. Add milk, salt, paprika, nutmeg and parsley. Mix well.
In a large 9x13 casserole dish, place half of the stale bread cubes. Top with half of the spinach. Now add half of the grated cheeses and then half of the tallegio. Now add half of the milk-egg combination. Press down so that the ingredients are compacted and there is no air. Repeat.
Bake for 45 minutes, until golden brown.