Heat a large saute pan over medium-high heat. When the pan is hot, add enough olive oil to lightly coat the bottom of the pan. Add the mushrooms and saute until the liquid is released and they are golden brown, about 5 minutes. Add the onion and the garlic and saute until the onions soften, about 5 more minutes. Season with salt and pepper. Carefully add the wine and cook until it reduces by 3/4. Check seasoning and serve.