• Preheat the oven to 425 degrees F.
• Peel the sweet potatoes, then slice in half lengthwise. Place the sweet potatoes cut side down on a cutting board. With a chopstick on each side of the potato as your guide, make thin slices down the potato, being careful not to cut all the way through (see photos above as a guide)
• Transfer the sweet potatoes to a parchment or silpat-lined baking sheet. Brush with most of the  olive oil.

For the savory version

• Add finely chopped herbs to the potatoes along with salt-- about 1/2 teaspoon of fine salt and freshly ground pepper. rubbing them into the slits. Roast for 30 minutes, until tender. Remove and brush with more olive oil. Transfer to a serving dish and sprinkle with finely chopped nuts. Let cool slightly and serve.

For the sweet version

• Brush with most of the maple syrup after the olive oil and sprinkle with a slight pinch of salt, I did about 1/8 teaspoon fine sea salt. The salt helps to contrast the sweetness, but you don't want them salty. Bake for 25 minutes, then remove and brush with more maple syrup and top with marshmallows. You may need to press down on the marshmallows to help them stick on top of the sweet potatoes. Return to the oven and bake another 5 minutes until the marshmallows have softened. Remove from the oven and place in a serving bowl, and sprinkle with the chopped nuts. Serve.