On medium low heat in a large pan melt the butter, then add the chopped onion and stir to combine. Cook until transparent, then add the rice and stir to combine.
Cook the rice for approximately 2 minutes, then add the wine and cook until it has evaporated (about 1-2 minutes). Stir occasionally.
Add the broth 1/2 cup at a time, stirring often. Lower the heat to a low simmer.
Taste for salt and add pepper. Cook approximately 20-25 minutes or until rice is al dente and not mushy, but a little moisture remains.
Remove from heat and stir in cheeses. Serve immediately sprinkled with fresh Parmesan cheese and chopped fresh parsley if desired.