Pre-heat the oven to 180C / 355F.
Place the chicken thighs in a large baking dish. Scatter the garlic cloves in between/over them, then grind over a generous amount of salt and pepper.
Scatter the chorizo pieces over the chicken, followed by the basil and then the tomatoes.
Drizzle over the olive oil and balsamic vinegar (if using), then bake for around an hour until the tomatoes are slightly charred and the chicken is cooked through and slightly browned where it pokes through the sauce. Toss and stir once half way through cooking.
Serve in dishes with toasted bread with olive oil or with a potato side dish.
