Preheat the grill to medium heat. If you’re using a grill pan on the stove, heat it over medium heat as well.
Slice the sweet potatoes into even rounds or planks, about 1/2 inch thick. This helps them cook evenly on the grill.
Toss the potatoes with olive oil, salt, and cinnamon. You want a light coating, just enough to carry the maple glaze later.
Grill the potato slices for 4 to 5 minutes per side, until they’re tender and have nice grill marks. If some pieces resist, give them a little extra time, they’ll soften up.
While the potatoes cook, toast the pecans in a dry skillet over medium heat for 3 to 5 minutes, stirring often, until they’re fragrant and lightly browned.
In a small saucepan, melt the butter and whisk in the maple syrup. Let it simmer for a minute, then pour in a pinch of salt. You want a glossy, cohesive glaze.
Brush the warm potatoes with the maple glaze, flipping and coating on both sides. This helps the glaze cling and sets nicely as it cools.
Scatter the toasted pecans over the glazed potatoes. If you like a little extra zing, finish with a light crack of black pepper.
Serve immediately while warm. The contrast between the crisp edges and soft centers makes a nice texture contrast.