Pumpkin Icebox Squares

From Josceline (shown without the whipped topping)

INGREDIENTS:

For the crust:
2 cups graham crackers
1/2 cup sugar
1/2 cup melted butter

for the filling:
29 oz. can pumpkin
6 oz. cream cheese, at room temperature
3/4 cup packed brown sugar
1 tsp cinnamon
1/4 tsp nutmeg
1/2 tsp salt
12 oz evaporated milk
2 tsp grated orange zest
3 envelopes unflavored gelatin
1/2 cup boiling water

For the topping:
3/4 cup whipping cream
1 1/2 TBL confectioner's sugar
1/8 tsp ground cinnamon

DIRECTIONS:
For the crust, heat the oven to 350. Combine the graham cracker crumbs and sugar in a medium bowl. Add the butter and stir until well-blended. Press the crumbs into the bottom and partially up the sides of a 9 x 13 inch baking pan. Bake until the crumbs have set, about 10 minutes. Let the crust cool on a wire rack.
In a large bowl, use an electric mixer on medium high speed to beat the pumpkin, cream cheese, brown sugar, cinnamon, nutmeg, and salt until smooth about 2 minutes.
In a small saucepan, combine the evaporated milk and orange zest and bring to a simmer over medium heath, about 3 minutes. Put the gelatin in a small bowl and gradually add the boiling water, stirring until the gelatin completely dissolves and thickens, about 3 minutes. Stir the gelatin into the milk mixture until it is well blended. Simmer, stirring until the gelatin is absorbed completely, 1-2 minutes.
Slowly beat the milk mixture into the pumpkin mixture, on low speed, until they're blended together, about 1 minute.
Pour all of the filling onto the cooled crust. Let the filling cool, about 30 minutes, then cover the pan with plastic wrap and refrigerate the dessert overnight to set it.
Just before serving, make the topping. Use an electric mixer on medium-high speed to beat the whipping cream, confectioners' sugar, and cinnamon until soft peaks form, about 2 minutes. Cut the dessert into squares, then transfer them to serving plates. Top each with whipped cream and a dusting of cinnamon.