A quintessential side dish, especially during this time of year, good old mashed potatoes are the inevitable go-to side for anything roasted.
How come mashed potatoes are so popular? Perhaps it's because they're a comforting reminder of Thanksgiving, their baby food like consistency, or possibly because virtually any flavor can enhance their taste and texture. Whatever the reason, mashed potatoes are a great side for any upcoming roast dinner you may be planning. For a variation that includes buttermilk and the subtle onion flavoring found in leeks and chives,
Buttermilk Mashed Potatoes with Leeks and Chives 
From America's Test Kitchen
2 pounds Yukon Gold potatoes, peeled and cut into 1-inch chunks
1 bay leaf
7 tablespoons unsalted butter (6 tablespoons, melted and cooled)
1 medium leek , white and light green parts, rinsed well, quartered, and cut into 1/4-inch slices
2/3 cup buttermilk , at room temperature
3 tablespoons minced fresh chives
Ground black pepper
- Place potatoes and bay leaf in large saucepan, add cold water to cover by 1 inch and 1 tablespoon salt.
- Bring to boil over high heat, then reduce heat to medium and simmer until potatoes break apart when paring knife is inserted, about 18 minutes.
- Drain potatoes, discard bay leaf, and return potatoes to saucepan set on still-hot burner.
- While potatoes are cooking, melt 1 tablespoon butter in small nonstick skillet over medium heat.
- Add leek and cook, stirring occasionally, until lightly browned and wilted, about 8 minutes.
- Using a potato masher, mash potatoes until a few small lumps remain.
- Gently add 6 tablespoons melted butter and buttermilk to small bowl and mix until combined.
- Add butter-buttermilk mixture, leeks, and chives to potatoes; using rubber spatula, fold gently until just incorporated.
- Adjust seasonings with salt and pepper; serve immediately.
The secret to best mashed potatoes