Heat the chicken stock and saffron on the stove. In a saucepan, heat the olive oil, cook the onion for 5 minutes or until tender, but not brown. Add the rice, stir to completely coat all the rice kernels. Add 1 cup of the hot stock, reduce the heat, and slowly cook allowing the stock to absorb slowly as it cooks. Add more stock as needed. You want the liquid to absorb and the rice to be perfectly al dente. Stir often with a wooden spoon.
When all the stock is absorbed and the rice perfect, quickly stir in the butter, cream, and cheese. Season and serve as an accompaniment, especially for braised lamb dishes.