Preheat oven to 350°.
To a medium bowl, add graham cracker crumbs, sugar, cinnamon and melted butter. Combine well then press into the bottom of a 9-inch pie dish along the bottom and up the sides. Place in oven and bake for 10 minutes. Set aside to cool.
For the filling, make a "double boiler" by placing a heat proof bowl over a saucepan of simmering water. Make sure the water doesn't touch the bottom of the bowl.
Add half-and-half, pumpkin, brown sugar, salt, cinnamon, nutmeg and cardamom to the bowl and stir to combine and until hot, about 5 minutes.
In another bowl, whisk the egg yolks. Stir 1-2 tablespoons of the pumpkin filling into the eggs to heat them (tempering). Then quickly whisk the egg mixture into the bowl with the hot pumpkin mixture.
Continue whisking for 4-5 minutes or until mixture is thickened. Remove from heat.
Dissolve the gelatin in 1/4 cup cold water. Whisk the gelatin into the (still hot) pumpkin mixture. Then add banana and orange zest and stir to combine. Set aside to cool.
Whip the heavy cream with an electric mixer (hand or stand) until soft peaks form. Add sugar and continue whipping until firm peaks form. Fold the whipped cream into the cooled pumpkin mixture then pour into the pie crust. Chill for at least 2 hours or overnight.
Serve with additional whipped cream.