Ham, Fontina and Spinach Bread Pudding

1 large baguette (about 3/4 lb)
1/2 stick unsalted butter, melted
2 onions, chopped
2 tablespoons olive oil
1 lb cooked ham, cut into 1/2-inch cubes
4 large eggs
1 quart whole milk
1 teaspoon salt
1/4 teaspoon freshly grated nutmeg
6 cups spinach leaves (about 1 bunch), coarsely chopped
3/4 lb Fontina cheese, grated

Preheat broiler.

Diagonally cut baguette crosswise into 3/4-inch-thick slices and brush both sides with butter. Toast on a baking sheet under broiler 3 inches from heat until golden, about 30 seconds on each side. Preheat oven to 350F.

Saute onions in oil in a 12-inch nonstick skillet over moderately high heat, stirring occasionally, until golden.

Add ham and saute, stirring occasionally, until ham is lightly browned.

Whisk eggs in a large bowl and whisk in milk, salt, nutmeg, and pepper to taste. Add toasted bread and toss gently. Transfer bread as saturated to a shallow 3-quart casserole, slightly overlapping slices. Add any remaining egg mixture.

Tuck spinach and ham between slices, reserving a little ham to sprinkle over top. Sprinkle cheese over pudding, lifting slices with a spatula to allow some to fall between them. Sprinkle reserved ham over pudding*.

Bake in middle of oven 45 minutes to 1 hour, or until puffed and edges of bread are golden and custard is set in middle.

Cooks' note:
•Bread pudding can be assembled 1 day ahead and chilled, covered. Increase baking time to 1 hour and 10 minutes if bread pudding is cold when put in oven, and cover top with foil after 45 minutes to prevent overbrowning.

Source: Gourmet Magazine