Preheat oven to 350°F (175°C). Line a 9×13 inch baking pan with parchment paper. Whisk together flour, brown sugar, and salt. Cut in butter until coarse crumbs form. Press half into the pan for the crust, set the remaining for streusel topping. Bake the crust for 10-12 minutes, or until lightly golden. Let cool slightly.
In a large bowl, beat softened cream cheese and granulated sugar until smooth. Add pumpkin puree, eggs, vanilla extract, cinnamon, nutmeg, ginger, allspice, cardamom, and salt. Beat until well combined.
Pour the cheesecake filling over the pre-baked crust. Sprinkle the remaining crumb mixture (streusel) evenly over the cheesecake filling. Bake for 35-40 minutes, or until the edges are set and the center is slightly jiggly. Let the bars cool completely in the pan, then refrigerate for at least 2 hours before cutting and serving.
