Preheat oven to 180°C. Cut the chicken in to 2 cm chunks. Peel and crush the garlic. Slice the cherry tomatoes in half. Combine stock with boiling water and set aside.
Heat a drizzle of oil in a fry pan over medium heat. Cook the chicken for 4-5 minutes or until golden. Stir through the garlic and Arborio rice and cook for 1 minute. Pour in the chicken stock liquid and bring to the boil for 2 minutes, stirring regularly. Remove from the heat and add the cherry tomatoes and baby spinach leaves.
Cover pan with aluminium foil and place in the oven for 15-20 minutes or until the stock has absorbed.
While the rice is cooking, finely grate the Parmesan cheese and slice the lemon in to wedges. Once the risotto is cooked, remove from the oven and stir through the cheese. Squeeze over lemon to taste and season with salt and pepper.