Grilled Sweet Potatoes with Soy Sauce, Maple, and Bacon

Put the potatoes in a medium pot, add enough water to cover by about ½ inch, and add enough salt so the water tastes slightly salty. Bring the water to a boil over high heat, reduce the heat, and simmer gently until the potatoes are nearly cooked but still firm, about 5 minutes. Drain and let them cool. You can do this a few days in advance.Preheat the oven to 400 degrees F. Add the bacon to a foil-lined baking sheet in one layer and bake until brown and crispy, about 15 minutes. Transfer to paper towels to drain, reserving the fat for another purpose.Combine the soy sauce, maple syrup, and sherry vinegar in a small pan, bring to a boil over high heat, and cook until the mixture thickens slightly, about 3 minutes.Combine in a blender with the butter (or over low heat, whisk in a piece of butter at a time), blend until smooth, and reserve.Preheat a well-oiled grill to cook over medium-high heat. Skewer the potatoes, leaving a little space between slices and leaving a couple of inches at the bottom of the skewer empty. Brush or drizzle some of the soy sauce mixture all over the potatoes. Grill the potatoes, flipping and brushing or drizzling on sauce occasionally, until the potatoes are lightly charred, shiny, and cooked through, 5 to 8 minutes.Transfer the skewers to plates, crumble on the bacon, sprinkle on the scallions, and drizzle on a little extra sauce. Eat.