Place the olive oil in a pot over medium heat. Add the onions and bacon and cook until limp. Season, to taste, with salt and pepper. Add the wine and bring to a boil. Add 1 cup of water and return to a boil. Continue cooking until the liquid is reduced by half.
Add the remaining water and the fava beans and bring to a boil. Lower the heat to a simmer and cook until the fava beans are tender, about 5 to 7 minutes. Add the mint leaves and cook for 1 minute. Serve hot or at room temperature.