1. Cook potatoes in boiling water to cover 30 minutes or until tender; drain and cool 20 minutes.
2. Meanwhile, whisk together olive oil and next 6 ingredients; let stand 30 minutes.
3. Peel potatoes, and cut into 1/4-inch-thick slices. Arrange potatoes in rows in a shallow 2-qt. baking dish, alternating Yukon gold and sweet potatoes. Pour olive oil mixture over potatoes; sprinkle with pecans and basil.