Preheat the oven to 350°F (180°C). Turn on the convection fan if you have one. Line a baking sheet with a silicone baking mat or parchment paper.
Slice sweet potatoes in half lengthwise (or cut each potato into 4 wedges for smaller side portions)
Use the point of a small sharp knife to lightly score the surface of the sweet potatoes in a diamond pattern, making cuts ½ inch (1 cm) deep at ½-inch (1 cm) intervals. (For smaller side portions, no need to score the wedges.)
Arrange the sweet potatoes cut side up on the prepared baking sheet and lightly oil the tops. Season with salt and pepper. Bake for 45 minutes.
Carefully brush the potatoes with maple syrup and evenly sprinkle with the fennel seeds and coriander seeds. Continue baking until glazed and tender, 15 minutes or so more.
Serve with a generous dollop of cilantro cashew pesto on top. Garnish with cilantro flowers, if any, and a few tender stems.