Preheat the oven to 350 degrees. \nUsing a mandoline, carefully slice the sweet potatoes into thin rounds, about 1\/16-inch thick (about the thickness of cardstock paper).\nIn a small pot, bring the cream to a light simmer over medium-low heat. Add This Little Goat went to Korea sauce, brown sugar and salt and whisk to combine. Set 1 oz. of the blue cheese aside and crumble the remaining into the hot cream mixture. Whisk until fully combined and the cheese has melted, about 1 minute. \nGrease an 8x8-inch baking dish with butter and place a single layer of sweet potatoes on the bottom of the baking dish. Cover with ¼ cup of cream mixture. Top with another layer of sweet potatoes and cream. Repeat until all ingredients are used, ending with sweet potatoes on the top. \nWrap tightly in foil and bake for about 1 hour, until the potatoes are soft and starting to brown. Remove the foil and top with reserved crumbled blue cheese. Return to the oven and continue cooking, uncovered, until the top begins to brown and the cheese is melty, about 15-20 minutes more. Top with sliced scallion greens and serve warm.