Put the potatoes in a large saucepan, cover with cold water and season generously with salt. Bring to a boil, reduce to a simmer and cook until the potatoes are tender, 15 to 20 minutes. Drain and let cool slightly. Gently smash with a fork or potato masher.
Meanwhile, in a large bowl, whisk together the oil, parsley, mustard, vinegar, shallots and jalapeno. Season with salt and pepper. Add the potatoes and gently combine. Serve at room temperature.
Recipe courtesy of Trisha Yearwood