Mix biscuits and butter together in a bowl until well blended. Press crust mixture into the base of a deep, 8-inch springform cake pan.
Place water in a small bowl. Sprinkle gelatin on top. Let stand until thickened, about 10 minutes.
Heat a saucepan over medium-low heat; fill with water to just below the bottom. Place bowl of gelatin mixture over water; heat until mixture is dissolved, 1 to 2 minutes.
Beat 1 1/2 cups plus 4 teaspoons cream in a chilled glass or metal bowl with an electric mixer until soft peaks form.
Beat cream cheese and white chocolate together in a separate bowl bowl using an electric mixer until even and smooth; fold in whipped cream. Add gelatin mixture gradually; mix until just combined. Pour batter over the crust. Chill until set, 8 hours to overnight.