1 kg (2½ pounds; about 3 large) sweet potatoes, scrubbed and halved lengthwise 360 grams (12.75 ounces; about 1 large) baking potato, scrubbed 2 large egg yolks, lightly beaten 1½ teaspoons kosher salt 250 grams all-purpose flour Whole nutmeg
Heat the oven to 425°F/220°C. Arrange the sweet potatoes cut sides down on a parchment-lined sheet pan. Roast until tender and easily pierced with a knife, 40 to 45 minutes. Bake the baking potato until tender and easily pierced with a knife, 60 to 70 minutes.
While the sweet potatoes are still warm, remove the skins and peel away the tough outer layer on the cut sides. Pass the sweet potatoes through a ricer or mash with a potato masher or fork, removing any stringy and undercooked pieces. Spread them on a paper towel–lined sheet pan and let cool for about 30 minutes. Thoroughly pat dry with paper towels before using (really sop up all that moisture!). Weigh out 450 grams (16 ounces) of the sweet potatoes (or, if you’re just under or over, use however much you have).
Repeat the process with the baking potato—you should be left with roughly 250 grams (8.8 ounces) of riced/mashed potato but use however much you have. Make the dough. You do not need to rest the dough before shaping.