In a large bowl, toss the sliced sweet potatoes in olive oil, harissa, maple syrup, and salt.
Arrange sliced sweet potatoes vertically in concentric circles in a 10-inch casserole or gratin dish (round, oval or even square will work!). Tuck garlic slices in between potatoes.
Cover gratin dish in foil and roast for 40 minutes.
Remove foil and bake for another 15-20 minutes until potatoes are tender and beginning to turn brown on top.
Meanwhile, prepare the dukkah. In a dry skillet, toast the sesame seeds, coriander seeds, and cumin seeds over low heat, stirring constantly, until they smell fragrant and sesame seeds begin to turn golden, 2-3 minutes.
Either in a coffee grinder or with a mortar and pestle, finely grind black peppercorns. Add the toasted seeds and lightly grind with a few pulses. Toss the ground seeds with chopped almonds and salt.
Top potatoes with 3 tablespoons dukkah (reserve remaining dukkah for later use) and serve warm.
This nutritional information has been automatically calculated, and as such, may be incomplete or inaccurate. Please reference the specific ingredients you use for the most accurate nutritional information.