Preheat the oven to 475°F, lightly oil a 12-inch round pizza pan, sprinkle with a little cornmeal and set aside.
In a small bowl, combine 1 teaspoon of the garlic with the truffle oil.
In a large skillet over medium heat, heat the olive oil. Add the onion and cook until soft, 7 to 8 minutes. Season with salt and pepper. Add the remaining garlic and continue cooking, stirring occasionally, until the onions are golden in color, 10 to 12 minutes.
Add the mushrooms and cook until tender, 5 to 6 minutes. Remove the pan from the heat.
Roll the pizza dough to fit the prepared pan. Spread the garlic-truffle oil mixture over the entire surface and pre-bake the crust for 5 minutes.
Remove the crust from the oven and spread the onion-mushroom mixture evenly on top. Place the cheeses evenly around the pizza and return to the oven and bake for 8 to 10 minutes.
Once the cheese is cooked to your liking, remove the pizza from the oven and sprinkle with fresh chives and drizzle of extra truffle oil. Rest for 5 minutes before cutting.