Heat oil in a large heavy pot over medium-high heat. Add onions, garlic, rosemary sprig, thyme sprig, and bay leaf. Cook, stirring often, until onions are golden brown and soft, 10-15 minutes. Remove pot from heat and add wine, stirring and scraping up any browned bits from bottom of pan. Return pot to heat and simmer until wine is reduced by half, about 3 minutes.