Prepare the Bread

• Preheat your oven to 350°F (175°C). Spread the bread cubes on a baking sheet and toast in the oven for about 10 minutes until slightly golden.

Sauté the Spinach

• In a skillet, sauté the chopped spinach over medium heat until wilted, about 3-4 minutes. Set aside to cool slightly.

Whisk the Egg Mixture

• In a large bowl, whisk together the eggs, milk, Dijon mustard, salt, pepper, and nutmeg until well combined.

Combine Ingredients

• In a greased 9×13-inch baking dish, layer half of the toasted bread cubes, followed by half of the sautéed spinach, and half of the Gruyère cheese. Repeat with the remaining bread, spinach, and cheese.

Pour the Egg Mixture

• Pour the egg mixture evenly over the layered bread and spinach. Press down gently to ensure all the bread is soaked.

Let It Soak

• Cover the dish with plastic wrap and refrigerate for at least 30 minutes, or overnight for best results.

Bake

• Remove the strata from the refrigerator and let it sit at room temperature for about 10 minutes. Sprinkle with additional Gruyère cheese and bake for 35-40 minutes, or until the top is golden and the egg is set.

Serve Warm

• Allow the strata to cool for a few minutes before slicing. Garnish with fresh herbs if desired.