No-Fuss Breakfast Bake Recipe by Tasty

Ingredients

• 3 tablespoons olive oil, divided
• 4 cups whole wheat bread, day-old, can use multigrain, or rye bread, cut into 1-inch (2 cm) cubes
• 1 yellow onion, thinly sliced
• 2 cloves garlic, finely chopped
• 6 cups fresh spinach, stems removed
• ½ lemon lemon zest
• 1 pinch red pepper flakes
• fine sea salt, to taste
• ½ teaspoon fresh ground black pepper, to taste
• 4 eggs
• 4 egg whites
• 1 ½ cups whole milk
• 1 ½ teaspoons whole grain mustard
• ¼ cup grated parmesan cheese, plus 2 tbsp, divided
• 3 tablespoons fresh chives, finely chopped