4cups whole wheat bread, day-old, can use multigrain, or rye bread, cut into 1-inch (2 cm) cubes
1yellow onion, thinly sliced
2cloves garlic, finely chopped
6cups fresh spinach, stems removed
½ lemon lemon zest
1pinch red pepper flake
fine sea salt, to taste
fresh ground black pepper, to taste
4eggs
4egg whites
1½ cups whole milk
1½ teaspoons whole grain mustard
¼ cup grated parmesan cheese, plus 2 tbsp, divided
3tablespoons fresh chive, finely chopped
Instrucciones
Preheat the oven to 350°F (180˚C).
Oil a 9x9-inch (23x23-cm) baking dish with 1 tablespoon of the olive oil and add the bread cubes in a single layer.
In a large skillet set over medium heat, add the remaining 2 tablespoons of the olive oil. Add the onions and garlic and cook until tender and starting to turn golden, 10-15 minutes.
In 2-3 batches, add the spinach and cook, tossing to wilt, 1-2 minutes.
Stir in the lemon zest and red pepper flakes and season with salt and pepper. Cook another 30 seconds then remove the pan from the heat and set aside to cool slightly.
In a large bowl, whisk together the eggs, egg whites, milk, and mustard. Season with salt and pepper and stir in ¼ cup (30 g) of the Parmesan.
Add the spinach mixture into the eggs. Stir in chives.
Transfer to the baking dish and mix gently to combine making sure the mixture is in an even layer. Top with remaining Parmesan.
Bake until the eggs are just set and the mixture doesn’t jiggle when you gently shake the pan, 35-40 minutes.