Prepare and bake cake mix according to package directions for cupcakes. Cool on wire racks.
In a small saucepan, sprinkle gelatin over water; let stand for 1 minute to soften. Heat over low heat, stirring until gelatin is completely dissolved. Remove from the heat; cool just to room temperature.
In a large bowl, beat cream and gelatin mixture until it begins to thicken. Add sugar and vanilla; beat until soft peaks form. Set aside 1 cup for decorating.
Spread remaining frosting over tops of cupcakes. Divide reserved frosting in half; tint one portion pink and the other yellow.
Use a toothpick to outline shape of heart, flower or sunburst on tops of cupcakes. Use medium star tip to pipe pink or yellow stars along outline. Fill in shape with piped stars as desired.