Grease and flour 13x9-inch pan. Reserve 1/4 cup cranberry-orange relish for frosting. In large mixer bowl, combine remaining cranberry-orange relish, dry cake mix, gelatin, water, oil and eggs. Blend and beat as directed on package. Bake at 350 degrees F. for 30-40 minutes until toothpick inserted in center comes out clean. Cool completely. Frost if desired.
Prepare frosting mix as directed on package, adding 1/4 cup reserved relish. Add red food coloring if desired.