Preheat your grill to medium-high heat (about 425°F/220°C). While the grill heats, wash the sweet potatoes well and pat them dry. You’ll want a clean, steady surface for even charring.
Slice the sweet potatoes lengthwise into 1/2-inch thick planks. This creates a sturdy surface that can soak up heat and develop a nice, caramelized crust.
In a large bowl, toss the potato planks with olive oil, salt, pepper, smoked paprika, and garlic powder until evenly coated. The oil helps conduct heat and the spices bring a comforting warmth.
Place the seasoned sweet potato slices directly on the grill grates. Cook for 4–5 minutes per side, until grill marks appear and the centers are tender when pierced with a fork.
Turn once halfway through cooking to ensure even color and crisp edges. If your grill runs hot, you can move the slices to cooler indirect heat for a few minutes to finish cooking without burning.
Once the potatoes are tender and nicely charred, remove them from the grill. Squeeze a little lime juice over the top and scatter fresh cilantro if using. A final pinch of salt can help bring out the flavors.
Serve warm as a side dish with grilled proteins, or top with avocado, yogurt, or a light herb chimichurri for a more substantial centerpiece.