Preheat oven to 400 degrees. Line a baking sheet with parchment paper. Slice the sweet potatoes into 1/4-inch medallions. Toss the medallions with coconut oil, maple syrup, apple cider vinegar and salt and pepper to taste. Arrange the medallions in a single layer on the prepared baking sheet and roast for about 30 minutes until soft inside and beginning to caramelize.