For the cherry grits with cinnamon topping, bring the jar of cherries to the boil in the saucepan. Add sugar and vanilla sugar. Mix the cornstarch with the cold water and stir into the hot cherries. Bring everything to the boil briefly.
Pour the cherry grits into small bowls or deep glass plates and let cool.
For the cinnamon topping, mix the sugar and cinnamon together. Whip the whipped cream with a whisk. Add the cinnamon sugar and continue beating until the cinnamon cream is semi-stiff.
Pour the cinnamon topping onto the cherry grits.