Yield: 10 to 12 servings
Total time: 2.25 hours
Ingredients
- 4 lbs Yukon Gold potatoes, peeled and thinly sliced
- 1.5 tsp kosher salt, plus more as needed
- 7 Tbsp unsalted butter, cubed and at room temperature
- 12 oz mild cheddar, coarsely grated (3c)
- 2/3 c sour cream, at room temperature
- 1/2 c grated Parmesan
- 1/2 tsp freshly ground black pepper
- 1/4 tsp freshly grated nutmeg
- 1/4 c hot milk, plus more as needed
- 1/2 c chopped chives (optional)
Instructions
Heat sous-vide to 194F. Evenly divide potatoes and 1.5 tsp salt between two bags. Seal and let out air. Cook until potatoes are completely tender, poking them several times to make sure, 1.5 to 2 hours (Check the bag after 15 minutes; you may have to let out some steam)
As potatoes cook, add butter, cheddar, sour cream, Parmesan, pepper, and nutmeg to a large bowl. Add the hot potatoes and milk, and mash until the cheese melts and the mixture is as smooth as you like it, adding more hot milk if the potatoes seem dry.
Taste and add more salt, if you like. Serve immediately, or transfer potatoes back to sous-vide bag to keep warm. Fold in chives just before serving.