In a medium saucepan whisk together milk, maple syrup and cornstarch. Cook over medium heat until thickened and slightly bubbly, stirring constantly . Remove from heat.
In a large bowl lightly whisk eggs. Gradually add warm milk mixture to eggs, whisking constantly. Return mixture to saucepan and cook for 3 minutes until thickened, stirring constantly. Remove from heat. Fold in pumpkin , pumpkin pie spice and salt.
Put equal parts water and ice cubes in a large bowl. Place saucepan in the ice bowl and stir constantly until mixture is cool to the touch.
In a chilled bowl beat cream and 1 tablespoon vanilla extract until soft peaks form. Place a small amount to another bowl for the topping. Fold pumpkin mixture into rest whipped cream.
Layer pumpkin whipped topping and crushed gingersnap cookies alternately in small mason jars. Add additional whipped cream on top and sprinkle with cinnamon. Serve immediately.