How to Make It
Stir together 1 can coconut milk, coconut sugar, and salt in a medium saucepan. Bring to a boil over medium-high; immediately reduce heat to medium-low to maintain a light simmer. Simmer, stirring occasionally, 30 minutes. During the last 5 to 8 minutes of cooking time, begin stirring often, scraping bottom of pan to incorporate the darker caramel bits into sauce. Once sauce has turned a dark amber and has thickened to coat the back of a spoon, remove from heat. Stir in coconut oil and vanilla.
Stir together remaining can coconut milk and ginger in a separate medium saucepan. Bring to a boil over medium-high. Remove from heat, and let stand 30 minutes. Pour through a fine wire-mesh strainer into a bowl, and discard solids. Stir into coconut-caramel mixture.
Wrap each sweet potato in heavy-duty aluminum foil. Place sweet potatoes on bottom grate of grill.
Light 1 charcoal chimney starter filled with briquettes. When briquettes are covered with gray ash, pour coals over sweet potatoes. Roast sweet potatoes, rotating occasionally, until completely tender, 40 minutes to 1 hour. Remove potatoes from coals, and let cool 10 to 15 minutes. Remove foil, and cut potatoes in half. Top evenly with butter and desired amount of coconut-caramel mixture.