1.Preheat oven to 200°C/180°C fan-forced. Line 8cm x 21cm loaf pan with a strip of baking paper.
2.Place tomatoes in prepared pan. Roast 10 minutes.
3.Meanwhile, combine egg, egg whites, cheese and garlic in medium jug.
4.Remove tomatoes from oven; reduce oven temperature to 160°C/140°C fan-forced.
5.Sprinkle tomatoes with zucchini and oregano; pour over egg mixture. Bake about 25 minutes or until set. Cool; cover then refrigerate.
6.The next day, cut slice in half, wrap in baking paper or plastic wrap. Pack spinach in an airtight plastic container. Pack slice and spinach in lunchbox with a freezer brick or frozen drink.
Make the night before. Make the slice and keep, covered, in the refrigerator.Note