This is a low-fat mashed-potato recipe, but you'd never know it. By browning the butter, you boost its flavor, so you can use less. And the buttermilk only sounds caloric--it's actually low in fat.
In a saucepan, cover the potatoes and garlic with lightly salted water and heat to boiling. Reduce heat to low, cover, and simmer until fork tender, about 10 to 15 minutes.
Meanwhile, in a small skillet or saucepan, heat the butter over low heat until it begins to brown, swirling the skillet, about 1 minute.
Drain the potatoes well and mash them with a potato masher or electric mixer until smooth. Blend in the buttermilk, chives, and browned butter. Add salt and pepper to taste.