Egg and Hash Brown Casserole

INGREDIENTS

• 8 center-cut bacon slices
• 1 1/2 cups chopped onion
• 8 ounces sliced shiitake mushroom caps
• 3 garlic cloves, minced
• 2 cups shredded hash brown potatoes (such as Simply Potatoes)
• 1/4 cup no-salt-added chicken stock (such as Swanson)
• 5 cups fresh baby spinach
• 2 tablespoons thinly sliced fresh basil
• 1/2 teaspoon kosher salt, divided
• 1/2 teaspoon freshly ground black pepper, divided
• 3 ounces reduced-fat Swiss cheese, finely chopped
• Cooking spray
• 1/2 cup 1% low-fat milk
• 6 large eggs, lightly beaten