- Pierce sweet potoates before to prevent them from bursting. Roast sweet potatoes whole in a 400 degree oven until just cooked through but not mushy, about 35 minutes to 1 hour, depending on the size of the potatoes (pierced with a sharp small knife, they should yield a slight resistance allowing just enough integrity to slice cleanly). Cool completely.
- Peel and slice the sweet potatoes into rounds, maintaining shape to the best of your ability for shingling on the cedar planks (discard any misshapen pieces and tapered ends).
- Shingle sweet potatoes onto pre-soaked cedar planks. Drizzle with just a little EVOO and season with sea salt. Place the cedar shingles on the cast iron ring of the OFYR grill, allowing the plank to steam, smoke and char, but taking care not to allow the plank to ignite. Keep a spray bottle of water on hand to put out any flare ups). Cook potatoes until heated through and tender, roughly 12 to 15 minutes.
- Meanwhile, toast the whole pecans in a dry cast iron pan over the OFYR until slightly charred and fragrant. Remove from heat and when cool enough to handle, crush slightly. Set aside. In a small sauce or sauté pan, heat neutral oil until just shimmering.
- Working in batches, fry whole sage leaves until crisp. With a slotted spoon, remove the nuts and drain on paper towels. Sprinkle immediately with fine sea salt. Melt butter in a small saucepan, allowing the solids to brown lightly, until it smells nutty and rich. Remove from heat and add reserved crushed pecans. Season with fine sea salt to taste.
- Carefully transfer hot cedar planks to a service platter. Alternately, use a spatula to gently separate the sweet potato from the charred plank and set upon a service platter, maintaining a shingled appearance.
- Spoon the hot pecan brown butter over the sweet potatoes and garnish attractively with crispy sage leaves. Scatter with a final flourish of crunchy salt before serving.