Preheat oven to 425. Line a baking sheet with foil and spray with cooking spray.
Peel yam. Cut potato in half down the middle, then into quarters length-wise. Cut each quarter into long, thin strips, trying to keep the fries similar in size for even cooking.
Throw all your yam strips into a bowl, drizzle with olive oil, then sprinkle with sea salt and pepper. Toss to coat.
When fries are evenly coated, place in rows on baking sheet, giving them space so that they're not touching one another.
Bake in oven for 10 minutes. Carefully turn the fries over. Fries should be turning brown and caramelized. The thin edges will be darker. Bake another 10 minutes. Check for doneness (this will depend on your oven). The fries should be evenly colored on both sides with crispy edges. A little bit of black crunchiness is good, but the whole fry should not be burnt. Mine ended up needing 5 more minutes, for a total of 25 minutes. Fries should be tender inside with crispy edges.
Remove from oven and allow to cool a few minutes. Serve with dipping sauce.
!To Make Dipping Sauce:
In a small bowl, mix mustard, mayonnaise, syrup, and cayenne pepper until smooth. Serve.