How to Make It
Preheat the oven to 425°. In a small bowl, whisk the miso with the mustard, 1/4 cup of the canola oil and 2 tablespoons of water.
In a large bowl, toss the mushrooms and sweet potatoes with the remaining 3 tablespoons of canola oil and season with salt and pepper. Spread the potatoes on a baking sheet. Roast for 15 minutes. Turn the potatoes and add the mushrooms. Roast for 10 minutes longer, until the potatoes are tender and golden and the mushrooms are browned. Transfer the potatoes and mushrooms to a platter and drizzle with the dressing. Garnish with chives and serve warm.