Olive Oil Mashed Potatoes

Place potatoes in heavy large pot and cover with cold water.  Boil over medium-high heat until potatoes are tender when pierced with fork, about 30-40 minutes.  Drain potatoes, reserving 1 1/2 cups cooking liquid.  Return potatoes to the dry pot and stir over medium heat until any excess liquid evaporates.  Add 6 tablespoons Olive Oil and mash until almost smooth. Mix in enough potato cooking liquid as needed to moisten. Season to taste with salt and pepper.
Transfer potatoes to large bowl and drizzle with remaining tablespoon olive oil and serve.