Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13-inch pan.
In a large bowl, stir together cake mix and gelatin mix. Make a well in the center and pour in oil, 1/2 cup water and eggs. Beat on low speed until blended. Scrape bowl, and beat 4 minutes on medium speed. Pour batter into prepared pan.
Bake in the preheated oven for 40 to 45 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.
To make the Glaze: In a medium bowl, combine lemon juice and confectioners' sugar. Beat in the melted butter and 1 tablespoon water. Poke holes in the top of the cake and pour glaze over.
