Twice-Baked Potatoes

Method

1. bake60 min
   400°F, on the rack, skins oiled and salted
   potatoes until a skewer meets no resistance — directly on the rack so hot air reaches every side; foil would steam them, and steam is the enemy of the crisp shell this dish is built on
2. prep8 min
   halved hot, 1/4-inch wall left
   each potato halved and the flesh scooped into a bowl while steaming — hot potato mashes smooth, cooled potato mashes gluey; the quarter-inch wall is structural, and a thinner one collapses under the refill
3. mash4 min
   while hot
   the flesh + butter first so it melts on contact, then sour cream + warm milk + salt + pepper — fat before liquid coats the starch, which is what keeps the mash light instead of gummy; half the cheddar folds in last
4. top5 min
   shells refilled, mounded
   the shells refilled proud of the rim with the rest of the cheddar over — the mound is not vanity: a level fill bakes flat and dense, the mound stays open and gets the browned peaks
5. bake20 min
   400°F, until the peaks brown
   until heated through and the cheese blisters — the second bake is shorter and hotter than the first; everything inside is cooked, so this bake is about the top and the reheat
6. top1 min
   with bacon and scallions after the oven, not before — baked-on bacon goes chewy and scallions scorch; added now, both stay what they are