In a large mixing bowl, dissolve the lemon gelatin in 2 cups of boiling water. Stir until the gelatin is completely dissolved.
Add 1 cup of cold water to the gelatin mixture and stir well.
Pour the gelatin mixture into individual glasses, filling each glass about ¼ full. Chill in the refrigerator for at least 1 hour, or until set. This creates your first layer.
Once set, spoon a layer of whipped cream over the jello in each glass. Chill again for at least 15 minutes to let the whipped cream set slightly.
Pour more jello mixture on top of the whipped cream layer and chill to set. Continue alternating between jello and whipped cream layers until you’ve filled each glass.
Garnish with a slice of lemon if desired before serving.