Tomato, Spinach, and Feta Frittata Veg GF 40 Mins Colleen McCabe Ingredients Instructions 1. Preheat oven to 400° F. 1 500mL carton egg whites 2. Grease a 9x9 round baking dish/cake 1 cup cherry tomatoes, sliced pan with olive oil or butter, making in half sure to grease the sides well. 1 red onion 3. Add ingredients, stirring gently 1 cup baby spinach, chopped with a fork. ¼ cup of feta 4. Place baking dish on top of a baking 2 tbsp olive oil or butter sheet just in case a bit of the oil rises above the egg white mixture. Salt and pepper to taste 5. Bake in the oven for 30-35 minutes until egg whites are ûrmly set. Source: The Girl on Bloor