Pre heat the oven to 180 deg C
Lightly toast the pitta bread and then cut it in half along the edges (giving you 2 oval shapes)
Using a knife, spread the tomato paste over the inside of each pitta half (the rough side)
Grate the cheddar and sprinkle over the top of each pitta, then slice the mozzarella and add over the cheddar
Thinly slice the onion, yellow pepper and mushrooms and add these toppings to the pittas
Sprinkle the dried herbs over the top
Place the pittas on a rack in the oven (to allow heat to flow under the pitta bread) and cook for 10 minutes, or until the cheese has melted and the vegetable have softened
Cut each pitta half into quarters for 8 mini pizza slices!