Stuffed Potato

This is a variation rather than a standalone recipe: it assumes you already have the book's method for potatoes on the half-shell, which is baked potatoes split, scooped, mashed with butter, hot milk and seasoning, then piled back into the skins and browned. The two additions change both the texture and the purpose of the dish.

• The base methodThe book's own directions for potatoes on the half-shell govern: bake the potatoes, halve them, scoop out the flesh leaving the shells intact, mash it with butter, hot milk and seasoning, then refill. No temperature or timing is given in the text; a modern oven at around 425F for 50-60 minutes will bake a large potato through.
• The egg whites are the hingeThe egg whites -- the recipe says only to add them to the potato mixture; it does not say to beat them. Beaten to soft peaks and folded in last, off the heat, they will lighten the filling rather than simply loosening it.
• Peanut butter has changedPeriod peanut butter was generally little more than ground peanuts and salt, stiff and oily; sweetened, stabilised spreads with hydrogenated fat came later. Unsweetened natural peanut butter, well stirred, is much closer than a modern sweetened spread, which will read as dessert against the potato.
• Warm it firstCold peanut butter seizes in mashed potato and leaves streaks. Thin it with a few spoons of the hot milk before it goes into the bowl.
• BrowningThe text gives no temperature or time. Return the filled shells to a hot oven (around 400F) on a sheet pan until the tops colour; peanut butter scorches faster than plain potato, so watch the tops rather than the clock.
• ServingTwo halves per person makes a light main course, one half a side dish. It is rich enough that it wants something sharp alongside - stewed tomatoes, a slaw, or pickled beets.