At a restaurant, people eat “pommes mousseline”, but at home they eat “purée” and here it is mashed potatoes. Of course, one can have great mashed if they add enough cream. But, at home, I prefer this much healthier recipe with Buttermilk. Buttermilk is quite low-fat and very high in protein, and in my opinion more than a match for cream. In fact, this would be a recipe that would be very suitable for athletes.
Add a large potato per person to a pot with salted cold water. Cook gently until well done. For a six potato recipe, bring one cup milk with a pinch of thyme to a boil. In a non-stick or cast-iron pot, sauté a crushed clove of garlic on low in 2tbsp olive oil. Transfer the potatoes and hand-mash them, then add the hot milk. Whisk in until smooth. Add the buttermilk, whisk again. Add more buttermilk if too dry. Salt.
Bake 10 minutes in the oven. Sprinkle with chives, add fresh ground pepper. Mmm, nice refreshing taste.
The milk can be replaced by a cup of broth for a different taste and of course the true pommes mousseline contain whole milk only.