Make it ahead: refrigerate the mashed potatoes for up to 2 days. To reheat, place ina double boiler or glass bowl set over (but not in) simmering water, adding whole milk as necessary to adjust consistency until heated through, 15-20 minutes
ready in about 50 minutes;
serves 8
You might need to buy:
- Kosher salt
- half and half
- unsalted butter
- small sprigs rosemary
- black peppercorns freshly grated or ground nutmeg for serving