Scrub the potatoes clean and add to a deep pot. Completely cover the potatoes with water, about 1/2 inch above the potatoes. Bring the potatoes to a boil and add 1/2 teaspoon of kosher salt. Boil the potatoes for 20 to 30 minutes or until they are very easily pierced with a fork and the skin pulls away from the potato where cut.

Drain the potatoes, and while still hot, use a paper towel to wipe the skin away from the potatoes, then add back to the warm pot. Gently smash the hot potatoes with the tines of a hand mixer and add the butter to the potatoes. Cover with a lid for the butter to melt, about 3-4 minutes.

Add the buttermilk to the pot and set it in the kitchen sink so the potatoes don't fly around the kitchen while whipping. Cream the potatoes with the hand mixer until smooth, rotating the pot counter-clockwise as you mix. Don't over mix the potatoes. Add the remaining 1/2 teaspoon of kosher salt and black pepper to taste. Stir in the crumbled blue cheese and chives. Garnish with additional blue cheese and chives.