Heat the olive oil in a large (12-inch) skillet. Add the onion and saute over medium heat until translucent, 5 to 10 minutes. Add the garlic and cook for 1 more minute. Add the wine and cook on high heat, scraping up all the brown bits in the pan, until almost all the liquid evaporates, about 3 minutes. Stir in the tomatoes, parsley, salt, and pepper. Cover, and simmer on the lowest heat for 15 minutes.