Preheat the oven to 325 °F.
In a bowl combine mushrooms, bell pepper, onion, passata, oregano and thyme to create pizza filling.
Peel zucchini into thick ribbons and use them to line 12 muffin tins.
Layer the toppings in the zucchini filled tins with mozzarella, 1 slice pepperoni, pizza filling, 1 slice pepperoni, and mozzarella.
Bake for 30 minutes. Leave to cool in pan for 5 minutes before removing. The zucchini may release water during cooking, laying it on a paper towel for a few minutes before serving will help absorb extra moisture. Enjoy.