Arrange sweet potatoes in a 9x13-inch aluminum foil pan. Stir butter and cinnamon together in a bowl and drizzle over potatoes. Cover pan with aluminum foil.
Bake sweet potatoes on the preheated grill, stirring occasionally, for 15 minutes. Stir honey and vanilla extract together in a bowl and drizzle over sweet potatoes. Return aluminum foil to cover pan. Continue cooking on the grill until sweet potatoes are tender, about 10 more minutes.
