Preheat an oven to 400 degrees. Line a rimmed baking sheet with parchment paper.
Place a wooden spoon (or wooden skewer) on either side of a sweet potato. Starting where the potato first meets the counter (this will prevent you from cutting off the end of the potato), create slices down the length of the potato, 1/8 inch thick. Use the wooden spoon handles as a guide so that the knife doesn't go all the way through the potoates. Repeat with the remaining potaotes.
In a small bowl, whisk together the butter, maple syrup, salt, herbs, and garlic. Brush half the mixture over the potatoes.
Bake for an hour. Halfway through baking, remove the potatoes from the oven. Put a fork under the potato in the middle of it, and gently lift it about two inches off the baking sheet. This will help the potato open up more (repeat with the rest of the potatoes). Then gently use a fork to spread open the potatoes from the top. Brush on the rest of the butter mixture and place back in the oven for the rest of hte baking time.