• Preheat oven to 400° roast. If you don’t have a roast setting, use bake.

Harissa Sauce

• Whisk oil, harissa, and vinegar in a large bowl to combine.

Sweet Potatoes

• Slice potatoes into thin rounds. I cut the sweet potatoes by hand, and if you do so, it will take you less than 10 minutes (and if you do a 1/2 recipe, it will take less than 5 minutes!). If your slices aren’t all even widths, don’t worry about it. We’re not looking for perfection here...this is a rustic looking casserole!
• Once sliced, transfer sweet potatoes to the large bowl with the harissa mixture. Use tongs to toss until sweet potatoes are thoroughly coated and season with kosher salt (this is an important flavoring step!).
• Arrange sweet potatoes in upright concentric circles in a 2-qt. baking dish (approximately an 8 x 8 inch square or 9” round). Pack the slices tightly. (Note: Reserve any extra harissa sauce from the bottom of the bowl to brush on the potatoes before serving.)
• Place sweet potatoes in the oven on the middle rack.
• Roast, brushing any accumulated harissa oil from the bottom of the casserole dish onto sweet potatoes every 10–15 minutes, until potatoes are soft and starting to brown on top, about 60-75 minutes. If the sweet potatoes need some help browning, turn on the broiler and move them to the top rack. Broil for 2 minutes or until desired brownness is reached. Keep an eye on them so they don’t burn.

Dukkah

• While sweet potatoes are roasting, toss together pistachios, sesame seeds, and fennel seeds on a small-rimmed baking sheet. Toast alongside sweet potatoes until golden brown, about 4-6 minutes until fragrant and browned. Let cool, then transfer to spice mill and coarsely grind. Set dukkah aside.

Serving Assembly

• Remove sweet potatoes from oven and brush with the leftover harissa mixture. Sprinkle with reserved Dukkah and serve.