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
1/2 cup 1% low-fat milk
6 large eggs, lightly beaten
Cook bacon in a large nonstick skillet over medium heat until crisp. Remove bacon from pan; crumble. Increase heat to medium-high. Add onion, mushrooms, and garlic to drippings in pan; sauté for 6 minutes. Add potatoes and stock; cook 6 minutes, stirring frequently. Add spinach, basil, 1/4 teaspoon salt, and 1/4 teaspoon pepper; cook 2 minutes or until spinach wilts. Remove from heat; let stand 10 minutes. Stir in crumbled bacon and cheese. Place mushroom mixture in an 11 x 7-inch broiler-safe glass or ceramic baking dish coated with cooking spray. Cover and refrigerate overnight.
Preheat oven to 350°.
Uncover dish. Combine remaining 1/4 teaspoon salt, 1/4 teaspoon pepper, milk, and eggs in a medium bowl. Pour egg mixture over mushroom mixture. Bake at 350° for 28 minutes.
Preheat broiler to high; remove dish while broiler preheats. Broil 3 minutes or until top is browned and just set. Let stand 5 minutes.