Heat oil in a large saucepan over medium-high heat. Add onion and sauté until softened.
Add garlic and sauté for another minute.
Add all remaining ingredients and lower the heat to medium. Simmer for about 15 minutes, until the sauce has thickened a bit.
Add to pasta of your choice.
Creamy Mushroom and Tarragon Soup with Wild Mushroom Bruschetta...