In a large saucepan, combine the potatoes, 1 teaspoon salt, and enough cold water to cover. Bring to a boil over high heat. Lower the heat to maintain a simmer and cook until fork tender, about 10 minutes. Drain the potatoes and return to the pan. Shake the pan over medium heat for about a minute to dry the potatoes. Transfer the potatoes to a food mill, ricer, or bowl.

Mash the potatoes through the food mill, ricer, or by hand into the pan. Stir in the low-fat milk, buttermilk, and dill warm over medium-low heat. Season with salt and pepper to taste and serve immediately.

Cook's Note: Do not heat the low-fat milk and buttermilk before adding to the potatoes or they will curdle