Combine sugar, cornstarch, and dry gelatin mix and stir well. Add water and cook until thick and clear over medium-high heat, stirring constantly to prevent scorching.
1 cup sugar, 3 tbsp cherry-flavored gelatin mix, 3 heaping tbsp cornstarch, 1 cup water
Set aside and let cool for about 30 minutes.
Drain cherries well and arrange them in the bottom of the baked pie shell.
1 15-ounce can sweet pitted cherries, 1 regular-sized pie crust
When the pie filling is cool, pour it over the cherries and chill the pie until ready to serve. Serve with whipped cream.