Dissolve the lemon gelatin in boiling water, stirring until completely dissolved. Add cold water and refrigerate until mixture is slightly thickened but not fully set, about 45-60 minutes.
While gelatin chills, beat cream cheese until smooth and fluffy. In a separate bowl, whip the heavy cream with powdered sugar and vanilla until stiff peaks form.
Fold the whipped cream into the softened cream cheese until well combined. Gently fold this mixture into the partially set gelatin along with the drained fruit cocktail.
Pour mixture into a 6-cup mold that has been lightly sprayed with cooking spray. Refrigerate for at least 4 hours or overnight until fully set.
To unmold, dip the mold in warm water for 10 seconds, place serving plate on top, and invert quickly. Refrigerate until ready to serve.