Heat two tablespoons butter in a heavy saucepan and cook the onion and garlic until wilted. Add the rice, saffron, salt and pepper then stir to coat the grains. Meanwhile, heat the stock and keep at a simmer.
Add the wine to the rice and cook until evaporated. Add a cup of hot stock and cook, stirring frequently, until the liquid is absorbed. Keep adding half cups of stock as needed, cooking gently.
When rice is done, stir in the chicken and remaining butter and heat through. Mix through the cheese and serve.