In a medium saucepan, bring the stock to a boil over medium-high heat. Add the porcini mushrooms. Remove the pan from the heat and set aside for 30 minutes until the mushrooms are tender. Using a slotted spoon, remove the mushrooms and set aside.
Reheat the stock to a simmer and keep warm over low heat.
In a large, heavy saucepan, melt 2 tablespoons of the butter over medium-high heat. Add the onion and mushrooms and cook until the onions are tender but not brown, about 3 minutes. Add the rice and stir to coat with the butter. Add the wine and simmer until the wine has almost evaporated, about 3 minutes. Add 1/2 cup of warm stock and stir until almost completely absorbed, about 2 minutes. Continue with remaining stock, adding 1/2 cup at a time, and allowing each addition to be absorbed, until the rice is tender to the bite and the mixture is creamy, about 20 to 25 minutes. Remove the pan from the heat. Stir in the Parmesan, Gorgonzola, chives, salt and pepper. Transfer the risotto to a serving bowl. Serve immediately.