Bring stock to a simmer until warm. Meanwhile in a 4-5 quart heavy pot, heat 2 tablespoons of butter and oil over high heat until foam subsides.
Add the rice and cook, stirring, for 4 minutes.
Add all the stock to the rice and cook, stirring frequently to prevent rive to stick, 15 minutes.
In the stock pan just used, add the heavy cream and the Gorgonzola and over low heat stir until all the cheese is melted. Season to taste with salt and pepper and remove from heat.
When rice has cooked add the cream sauce and simmer, stirring until the sauce is absorbed and the rice is tender, and the risotto is thickened.
Remove from heat, fluff with a fork and add the Parmigiano, the remaining 4 tablespoons butter. Mix well and serve immediately