1) Take a medium-size saucepan and melt butter in it over medium heat.
2) Stir in scallions and garlic. Saute for 2 minutes.
3) Blend in tomato sauce, brown sugar, cinnamon, and 1/4 cup water. Boil the mixture and cook over high heat. Stir constantly for 2 minutes. Decrease heat to medium-high and simmer for 3 minutes , stirring occasionally.
4) Add sherry and simmer for further 5 minutes.
5) Shift sauce to a small bowl and drizzle cinnamon on top.