In a 4-qt. dutch oven over moderate heat, heat the butter and oil (from sun-dried tomatoes). Add the onion and saute just until it begins to soften (about 2 minutes).
Add the rice to the pan and stir for one minute, making sure the grains are all well coated. Add the wine and stir until it is completely absorbed.
Begin to add the simmering broth one-half cup at a time, stirring frequently. Wait until each addition is almost completely absorbed before adding the next half-cup, reserving about 1/4 cup to add at the end. Stir frequently to prevent rice from sticking.
Add the sun-dried tomatoes and tomato paste after the rice has been cooking for about 10 minutes. Continue to add the broth, one-half cup at a time.
After the rice is tender (about 18-25 minutes), add the final broth and the fontina, parsley and Parmesan. Stir for 1-2 minutes until cheeses are melted and combined with the rice.