Heat the stock in a pot and keep it aside, simmering.

In a large, deep skillet heat half the oil and sauté the leeks, fennel bulb, and garlic. Add the rice and stir for 1 to 2 minutes.

Lower the heat. Pour in half the wine and as soon as it steams off, add the remaining wine. When that is absorbed, add half a cup hot broth. Continue to stir until all the liquid is absorbed. Repeat the procedure until the rice is tender but al dente, using up most of the hot broth. Season to taste with salt and pepper. About 5 to 6 minutes before removing the rice, mix the saffron with one tablespoon of hot broth and add it to the risotto. Stir to distribute evenly. When the rice is ready, remove and stir in the grated Kasseri. Serve hot.