01 - Preheat oven to 350°F. Line an 8x8-inch baking pan with parchment paper, allowing overhang for easy removal.
02 - In a medium bowl, combine flour, brown sugar, and salt. Cut in cold butter using a pastry blender or fork until mixture resembles coarse crumbs. Press firmly and evenly into the bottom of the prepared pan.
03 - Bake crust for 10 minutes until lightly set. Remove from oven and set aside.
04 - In a large bowl, whisk together pumpkin puree, maple syrup, brown sugar, eggs, pumpkin pie spice, vanilla, and salt until completely smooth and well combined.
05 - Pour the pumpkin mixture evenly over the warm pre-baked crust. Use a spatula to spread into a uniform layer.
06 - In a small bowl, mix flour, brown sugar, cinnamon, salt, and melted butter until crumbly and combined.
07 - Sprinkle the streusel mixture evenly over the pumpkin filling. Bake for 30 minutes until the center is set and the topping is golden brown.
08 - Cool completely in the pan on a wire rack, about 1 hour. Using the parchment overhang, lift out the bars and cut into 16 squares. Serve at room temperature or chilled.