1. Heat oven to 350 degrees F. Coat a 9-inch pie dish with nonstick cooking spray.Crust:
2. Combine macaroons and macadamia nuts in a food processor. Pulse until ground to crumbs. Add butter; pulse until blended.
3. Press crumbs into bottom and up side of prepared pie dish. Bake at 350 degrees F for 15 minutes. Cool on wire rack.Filling and topping:
4. In large bowl, whisk milk, pudding mix and banana extract for 1 to 2 minutes, until mixture thickens. Fold in banana. Pour into crust.
5. Combine 3 tablespoons water and gelatin in a glass bowl. Let stand 5 minutes. Microwave for 15 seconds or until melted. Cool to room temperature.
6. Beat heavy cream with mixer until it begins to thicken. Beat in gelatin mixture and then sugar. Beat to stiff peaks, then spread over top of filling. Refrigerate 3 hours, then top with chopped nuts, if desired.