Preheat your oven to 425°F (220°C). Scrub the sweet potatoes and pat them dry.

Place a sweet potato between two chopsticks on a cutting board. Carefully make thin, vertical slices (about 1/8-inch apart) across the potato, stopping when your knife hits the chopsticks. Repeat with the second potato.

Rub the sliced potatoes with olive oil and season generously with salt and pepper. Place on a baking sheet and roast for 30 minutes.

While the potatoes roast, melt butter in a saucepan over medium heat. Continue cooking until brown specks appear and it smells nutty. Remove from heat and stir in the fresh sage leaves.

Remove potatoes from the oven and brush generously with about half of the sage brown butter, getting it between the slices. Return to the oven and roast for another 20-30 minutes, until tender and crispy.

Transfer potatoes to a platter. Drizzle with the remaining sage brown butter and sprinkle with toasted pecans before serving.