Spinach and Cheese Strata

Ingredients

• 2 tablespoons Dijon mustard
• 9 large eggs
• 1 10-oz package frozen spinach
• 2 ¾ cups milk
• 8 cups French or Italian bread
• 1 teaspoon salt
• 3 tablespoons unsalted butter
• + 5 more ingredients
• • 1 ½ cups onion (1 large)
  • ¼ teaspoon freshly grated nutmeg
  • ½ teaspoon black pepper
  • 6 ounces coarsely grated Gruyère
  • 2 ounces finely grated Parmigiano-Reggiano

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 re...

View full recipe at Epicurious