Preheat oven to 350℉ and grease a metal 9x13 baking pan. Set aside.
In a food processor, chop pecans into small pieces. Add flour, brown sugar, salt and butter. Process in 1 second pulses until crumbles form.
Transfer mixture to prepared pan and press evenly into the bottom.Bake at 350℉ for 15 minutes or until firm and fragrant. Set aside.
Pumpkin Layer
In a large bowl, vigorously whisk all the pumpkin filling ingredients until smooth.
Transfer mixture to partially baked crust (it’s okay if it’s still warm). Spread into an even layer and bake for 30 minutes. Prepare the pecan topping while the bars bake.
Pecan Topping
In a bowl, toss together the pecans, brown sugar and melted butter until the nuts are evenly coated.
After 30 minutes of baking, remove the bars from the oven and sprinkle the pecans over the top. Return the bars to the oven to bake 10 minutes longer. Bars are done when the edges are set and the enter jiggles slightly when gently shaken.
Cool completely before cutting into 15 large squares. Serve at room temperature or chilled.
Notes
Baking pan: Use a metal pan, not glass. Glass retains heat longer and may over-bake the crust and sides of the bars.Pumpkin pie spice: Make your own by whisking together 1 1/2 teaspoons cinnamon + 1/2 teaspoon ground ginger + 1/4 teaspoon ground nutmeg + 1/4 teaspoon ground allspice or cloves.Store covered in the refrigerator for up to 4 days.Freeze for up to 2 months. After the bars have cooled completely, flash freeze for 1 hour or until firm. Then, wrap in plastic wrap and store in an airtight container in the freezer. Defrost in the refrigerator before serving.