Prep time: 30 minutes
Chill Time: 8 hours
1 (10oz.) package of frozen spinach (thawed)
1 1/2 cups finely chopped onion
3 tablespoons unsalted butter
1 teaspoon salt
1/2 teaspoon black pepper
1/4 teaspoon freshly grated nutmeg
8 cups cubed (1") French/Italian bread
6 oz. coarsely grated Gruyere (2 cups) cheese
2 oz. finely grated Pamesan (1 cup) cheese
2 1/4 cups milk
4 large eggs
2 tablespoons Dijon mustard
Squeeze handfuls of spoinach to remove as much liquid as possible, then coarsely chop.
Cook onion in butter in a large skillet over moderate heat, stirring, until soft 4-5 minutes.
Add 1/2 teaspon salt, 1/4 teaspoon pepper and nutmeg; stir 1 minute.
Stir in spinach, the remove from heat.
Spread one third of bread cubes in buttered 3 quart gratin dish or other shallow baking dish and evenly top with one third of spinach mixture.
Spinkle one third of each cheese.
Repeat layering twice - ending with cheeses.
whisk together milk, eggs, mustard and remain 1/2 teaspoon salt and 1/4 teaspoon peper in a large bowl and pour evenly over strata.
Chill strata, covered with plastic wrap, at least eight hours (for bread to absorb custard).
Preheat oven to 350 degrees.
Let strata stand at room temperature for 30 minutes.
Bake strata uncovered, in middle of oven until puffed and golden brown and cooked through, 45- 55 minutes.
Let stand 5 minutes before serving.