Choose similarly sized sweet potatoes so the slices cook evenly. If the glaze thickens too quickly before the potatoes are tender, add 1–2 tablespoons of water and continue cooking. For extra shine, baste the slices with the syrup just before serving. Leftovers keep in an airtight container in the fridge up to 4 days; reheat gently on the stovetop with a splash of water.