Miso Sweet Potatoes Inspired by melting potatoes, we gave the same treatment to sweet potatoes. The results? Roasted potatoes that are creamy on the inside but perfectly crisp on the outside. Adding miso to the butter mixture adds great umami flavor and helps the potatoes caramelize while baking. Don't skip lining the baking sheet or the miso-butter might burn on the pan and cause the sweet potatoes to stick.