Garlic and Sour Cream Mashed Potatoes

4 cups low-sodium chicken or vegetable broth
1 pound Yukon gold potatoes, peeled and cut into 1-inch chunks
4 cloves garlic, peeled
1/4 cup low-fat sour cream
1 tablespoon olive oil
3/4 teaspoon salt
1/4 teaspoon freshly ground pepper

In a 4-quart saucepan, combine broth, potatoes, and garlic over high heat; bring to a boil. Reduce heat to low and cover; simmer until tender, about 15 minutes. Drain potatoes and garlic, reserving broth. In a large bowl, mash potatoes and garlic with 1/2 cup reserved broth (if needed), sour cream, oil, salt, and pepper until smooth. Serve warm.