Quarter the red potatoes and add them to a steamer basket. Add the basket of potatoes to a large pot of boiling salted water and boil for 8 to 10 minutes.
The water should be well seasoned and salty like the ocean. In the meantime, heat the buttermilk, butter, sour cream, and horseradish in a small pot over low heat. Keep warm.
Remove the potatoes and drain the water from the pot. You’ll know the potatoes are done when you pierce them with a fork, remove them from the water, and they slide off the fork with ease.
Transfer the potatoes back to the drained pot and add in the warm buttermilk mixture. Mash using a hand masher until the desired consistency is reached. I like a few little chunks in there.
Season with salt, pepper, and chives, and fold together until combined. Transfer to a bowl and add some melted unsalted butter and garnish with additional chopped chives.