Spinach and Cheese Strata | Healthy Make-Ahead Recipe

Ingredients

• 1 Tbsp olive oil
• 1 large onion, chopped
• 1/8 tsp salt
• 1/4 tsp black pepper
• 1/4 tsp ground nutmeg
• 1 package (10 oz) frozen spinach, thawed and chopped
• 3 1/2 cups 1-inch thick whole wheat bread cubes
• 3 oz grated reduced-fat cheddar cheese
• 1 oz grated Parmesan cheese
• 1 cup 1% milk
• 4 large eggs
• 1 tsp Dijon mustard