Preheat oven to 425 degrees F. Line a rimmed baking sheet with foil.
Peel sweet potatoes and cut into 1/2-inch-thick wedges. Place on the prepared baking sheet, drizzle with oil and toss well. Spread the wedges in a single layer and bake until tender when pierced with a knife, 25 to 30 minutes. Remove from the oven; season with salt and pepper.
Meanwhile, combine vinegar and honey in a small saucepan. Bring to a boil over medium-high heat and cook until syrupy and reduced to 1/3 cup, 12 to 15 minutes. (Watch the syrup carefully during the last few minutes of reducing to prevent burning.) Swirl in butter and remove from heat. Drizzle the warm sauce over the roasted sweet potatoes.