Bacon Spinach Breakfast Casserole with Gruyère

Bahan-bahan (8 porsi)

• Cooking spray
• 8 slices center-cut bacon (chopped)
• ½ cup finely diced shallots
• 5 -ounce package baby spinach
• 8 ounces shredded Gruyère cheese (2 cups total (I like Finlandia))
• 12 large eggs
• 1 cup nonfat milk
• ½ teaspoon kosher salt
• Freshly ground black pepper (to taste)