Fry the oregano, tomatoes and sugar, a little splash of vinegar and some salt and pepper, then simmer for 20 mins until the sauce is really thick. Stir in the chicken, chives and garlic infused oil and transfer to a baking dish.
Heat oven to 220C/200C fan/gas 7. Tear over the mozzarella in chunks, then scatter over with the gluten free breadcrumbs with a bit more ground pepper.
Bake for 20 mins until the chicken is piping hot through and the top is golden and bubbling. eat with mash, jacket potatoes, rice or gluten free pasta.