Preheat the oven to 425 degrees F. Line a baking sheet with aluminum foil and spray with nonstick cooking spray.
Wash and dry potatoes. Make a series of 1/8-inch slices along the top of each potato, stopping 1/2 inch from the bottom so you don't slice all the way through the potatoes.
Add the potatoes to the baking sheet and drizzle with some olive oil. Rub the olive oil all over the potatoes. Bake sweet potatoes for 40 minutes. Towards the end of the 40 minutes, whisk all of the Herb Butter ingredients together (not too early, or the butter will harden).
Remove the potatoes from the oven and brush in between the slices with the Herb Butter.
Return to the oven and bake another 10-20 minutes OR until the center potato slices are very tender. Brush sweet potatoes with any of the butter that has accumulated at the bottom of the pan. Season with additional salt and pepper to taste. Serve with Sour Cream or Herb Goat Cheese or see Gouda option below.
Optional: When potatoes are fully cooked, remove from oven and distribute Gouda evenly in between every few potato slices. Return potatoes to oven and cook just until cheese is melted, 3-5 minutes more.