SPINACH AND CHEESE STRATA

Steps:

• Squeeze handfuls of spinach to remove as much liquid as possible, then finely chop.
• Cook onion in butter in a large heavy skillet over moderate heat, stirring, until soft, 4 to 5 minutes.
• Add 1/2 teaspoon salt, 1/4 teaspoon pepper, and nutmeg and cook, stirring, 1 minute.
• Stir in spinach, then remove from heat.
• Spread one third of bread cubes in a buttered 3-quart gratin dish or other shallow ceramic baking dish and top evenly with one third of spinach mixture.
• Sprinkle with one third of each cheese.
• Repeat layering twice (ending with cheeses).
• Whisk together milk, eggs, mustard, and remaining 1/2 teaspoon salt and 1/4 teaspoon pepper in a large bowl and pour evenly over strata.
• Chill strata, covered with plastic wrap, at least 8 hours (for bread to absorb custard).
• Preheat oven to 350°F.
• Let strata stand at room temperature 30 minutes.
• Bake strata, uncovered, in middle of oven until puffed, golden brown, and cooked through, 45 to 55 minutes.
• Let stand 5 minutes before serving.
• note: Strata can be chilled up to 1 day.
• Let stand at room temperature 30 minutes before baking.