First, preheat the oven to 400℉.
Next, you want to find something to stick on the sides of the potatoes to keep you from cutting all the way through. Then, slice the potatoes about ¼ in slices leaving the sweet potato unsliced through the bottom. This will create the classic hasselback spread, later.
Now, place the cut sweet potato in aluminum foil. Pour olive oil or any cooking oil over the top. About a tablespoon or two. You do not need to make sure each slice has oil going on it.
Then, wrap the sweet potato into the foil and bake for 45 minutes.
After that time is up, remove from the oven and do not open the foil. Allow the sweet potato to sit for about 15-20 minutes while it cools and finishes cooking.
Lastly, unwrap the hasselback sweet potato and carefully transfer to a plate. Pour on melted butter, salt and pepper and enjoy. Or any topping of your choice.