Preheat oven to 325°F. Place a large shallow pan of water on bottom rack of oven. Spray 9-in. springform pan with vegetable pan spray.
For crust, combine crumbs with sugar and melted butter; press into bottom and up sides of pan. Bake 8 minutes; cool completely.
Lower oven temperature to 250°F.
For filling, combine hot water and instant coffee; stir until dissolved. In large bowl, beat cream cheese, sugars and flour with electric mixer until smooth and creamy, about 4 minutes. Add eggs, one at a time, mixing well after each. Add vanilla, sour cream and coffee mixture; blend well. Pour filling over baked crust.
Bake on center rack of oven, above pan of water, 1 to 1-1/4 hours or until filling is set but still jiggles slightly in center when pan is gently shaken. Turn oven off and with door closed, allow cheesecake to remain in oven for 1 hour. Transfer to cooling grid to cool completely. Refrigerate 3-4 hours or overnight until cheesecake is firm.
Sprinkle with cocoa powder and chocolate curls before serving, if using.