Lower the oven temperature down to 300 degrees F.
In a large mixing bowl, combine the pumpkin puree, brown sugar, eggs, cinnamon, nutmeg, ginger, and salt. Set aside.
Using an electric mixer, beat the cream cheese until smooth.
Add in the maple syrup and bourbon one at a time, mixing after each addition until smooth.
Mix in the sour cream and pumpkin mixture until smooth, making sure not to over mix the batter.
Pour the filling over the pre-baked crust.
Bake for 1 hour and 40 minutes, or until the center shows little to no movement when the pan is tapped.
Set aside to cool for at least 15 minutes to 1 hour before moving to the refrigerator to chill for at least 3-4 hours before serving.