Place vanilla wafers in a food processor and pulse until finely chopped.
Add ¾ cup sugar and melted butter; pulse to incorporate.
Grease bottom and sides of 9-inch spring form pan; press mixture into bottom and slightly up the sides of the pan; place in freezer for 30 minutes.
In a medium bowl, using an electric mixer, beat cream cheese and remaining sugar until smooth.
In a separate medium bowl, combine gelatin and boiling water; whisk until dissolved; set aside.
Zest the orange and set aside.
In another medium bowl, whip heavy cream, confictioners's sugar and vanilla until stiff peaks form.
Add ½ of the whipped cream mixture to the cooled gelatin and add orange zest; whisk to blend; set aside.
Fold remainder of whipped cream mixture into cream cheese mixture.
Spread ½ of the cream cheese mixture over the crust.
Pour 2 cups of orange whipped cream mixture over cream cheese mixture.
Gently spread remaining cream cheese mixture over orange mixture.
Pour remaining orange whipped cream mixture over plain cream cheese mixture.
If desired, take a butter knife and gently glide through cream cheese layers to swirl.
Refrigerate for at least 6 hours.
Remove from the refrigerator, top with whipped cream and orange slices, if desired.
