• Preheat oven to 350°F. Line an 8 × 8-inch baking dish with parchment paper, leaving an overhang on the sides to make the bars easier to lift out. Lightly spray with nonstick cooking spray.

Shortbread Crust

• In a medium bowl, whisk together the flour, sugar, and salt.
• Add the softened butter and mix with a fork or your hands until the mixture forms a moist, crumbly dough that holds together when squeezed. Press firmly and evenly into the prepared pan.
• Bake for 15 to 18 minutes, or until the edges are lightly golden. While the crust bakes, prepare the pumpkin cream filling.

Pumpkin Cream Filling

• In a medium saucepan over medium heat, whisk together the pumpkin, milk, heavy cream, brown sugar, cornstarch, salt, cinnamon, ginger, nutmeg, and cloves. Cook, whisking frequently, for 4 to 6 minutes, or until the mixture is hot and noticeably thickened. Reduce the heat to low.
• In a separate medium bowl, whisk together the eggs and vanilla. Slowly whisk about ½ cup of the hot pumpkin mixture into the egg mixture to temper the eggs.
• Pour the tempered egg mixture back into the saucepan. Cook over low heat, stirring constantly, for another 2 to 3 minutes, or until the filling is smooth and thickened to a pudding-like consistency. Do not let it boil.
• Immediately pour the hot pumpkin filling over the pre-baked crust and spread it into an even layer.

Crumble Topping

• In a small bowl, whisk together the flour, brown sugar, and salt. Add the melted butter and stir with a fork until moist crumbs form. Gently squeeze some of the mixture together with your fingers to create a combination of small crumbs and larger clusters.
• Sprinkle the crumble evenly over the warm pumpkin filling.
• Bake for 30 to 35 minutes, or until the crumble is golden brown and the center has only a slight jiggle.
• Let the bars cool completely in the pan on a wire rack, about 1 hour. Refrigerate for at least 2 hours, preferably longer, before lifting them out of the pan and cutting into bars.