Ingredients:

  • 6 large egg whites (about 180g/6oz), room temperature
  • 2 tablespoons milk (any kind - whole, skim, almond, or oat milk)
  • 1 tablespoon olive oil
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • Pinch of red pepper flakes (optional)
  • 1 tablespoon olive oil
  • 1 cup (about 75g/2.6 oz) fresh spinach, roughly chopped
  • 1/4 cup (about 40g/1.4 oz) red onion, finely diced
  • 1/4 cup (about 30g/1oz) crumbled feta cheese
  • 2 tablespoons chopped fresh parsley (or chives) for garnish (optional)

Instructions:

  1. Preheat oven to 375°F (190°C).
  2. In a large bowl, whisk together the egg whites, milk, salt, pepper, and red pepper flakes (if using) until light and frothy. Do not over-whisk.
  3. Heat 1 tablespoon of olive oil in the oven-safe skillet over medium heat. Add the red onion and sauté until softened, about 3-5 minutes. Add the spinach and cook until wilted, about 1-2 minutes. Remove from heat.
  4. Pour the egg white mixture over the spinach and red onion in the skillet. Sprinkle the feta cheese evenly over the top.
  5. Bake in the preheated oven for 25-30 minutes, or until the frittata is set and lightly golden brown. A knife inserted into the centre should come out clean.
  6. Let the frittata cool slightly in the skillet. Garnish with fresh parsley or chives (if using). Cut into wedges and serve immediately.