Add buttered corn kernels in a pan on a medium flame and cover with a lid until they pop. Be careful not to burn the popcorn. In another pan, add sugar and let it melt. Then add water and butter. Mix the butterscotch sauce well. Remove popcorn in a bowl and pour the butterscotch sauce. Sprinkle chilli flakes and salt. Mix well. Serve butterscotch popcorn in a tub and garnish with gems.