Preheat oven to 180°C or 350°F fan forced.
Line a standard size 12 muffin silcone tray with ham slices and put on a baking tray for easy transfer to oven - if you are using a metal tin, lightly grease with oil or butter of choice before putting ham in.
Add whole eggs, egg whites, quark, onion powder, garlic powder, oregano, black pepper and stock concentrate to mixer bowl. Beat for 30 sec/speed 5.
Add mushrooms and baby spinach to mixture and combine for 10 sec/speed 2.
Fill each ham case with quiche mixture. Garnish with tomato slices and cheese.
Bake in oven for 45 min or until set. Let quiches sit for 10 min before serving.