In a Dutch oven, bring the chicken broth, butter, salt, and saffron to a boil.
Add the rice and simmer it uncovered for about 20 minutes until all the broth is absorbed. The rice should still be al dente. Add some water if more liquid is needed to cook the rice.
Take the pot off the heat and add the cheese. Then, pour the rice on a foil lined cookie sheet. Spread it out and chill it while you prepare the rest of the ingredients.
In a second Dutch oven, with a deep fry thermometer clipped on it, heat one inch of oil to 350 degrees.
Prepare a breading station with one bowl filled with breadcrumbs. In the second bowl, whisk together the flour with one cup of water. The consistency of the batter should be like pancake batter.
Form the arancini by scooping up the rice in a quarter cup measuring cup. Using your finger, make a whole in the middle and place a cheese cube inside. Push the rice out and shape it into a compact ball. Repeat with the other 15 arancini balls. It helps to wet your hands for this step.
When all the arancini are formed, rub each one all over with the batter, and then cover them completely in crumbs.
When the oil is at 350 degrees, fry 4 balls at a time, until golden brown, about 5 minutes. You will need to turn them over halfway through. Drain them on a wire rack set over a sheet pan. Let the oil return to 350 degrees between batches.