Golden Mashed Potatoes

4 garlic cloves
2 T olive oil
6 cups water
2 lbs potatoes - peeled and cubed
1 lb sweet potatoes
1 t salt
3/4 c. buttermilk
1/4 cup butter
3/4 t salt
1/2 t pepper

Cook garlic in hot oil in a dutch oven stirring occasionally over medium heat - 3 minutes. Add 6 cups water and next 3 ingredients; bring to boil. Reduce heat - cover and cook. 20 minutes or until tender. Drain potatoes and return to dutch oven. Cook, stirring constantly over medium heat 30 seconds. Remove from heat. Add buttermilk and remaining ingredients; mash with a large fork to desire consistence. Serve immediately.