Fry the onions, peppers and mushrooms until softened
Once soft, add some black pepper, the garlic puree and chilli flakes
Slice the pepperoni in to strips and add this to the pan with the oregano
Cook for a few more minutes, then add the rice to the pan and stir well
Once the rice is mixed in, add the passata and stir for a few minutes
Add the balsamic vinegar, and then the chicken stock little at a time, stirring constantly, adding more stock once it's been absorbed, this will take around 30
Once stock is absorbed, stir in the tomato puree and add the cherry tomatoes and grated mozzarella to the pan, keep stirring