Preheat oven to 350° F. Line an 8×8 square baking pan with parchment paper. Spray lightly with nonstick cooking spray. Set aside.
To make the crust, stir together the flour, brown sugar, and salt in a medium bowl. Using a pastry blender or a fork, cut the butter into the dry ingredients until the mixture forms small, coarse crumbs.
Press the crust mixture into the bottom of the prepared pan, pressing it down firmly into the pan. Bake for 15 minutes or until the edges are golden and the top feels firm when lightly touched. Set aside.
For the Maple Pecan Filling:
To make the filling, place a saucepan over medium heat and add the butter, brown sugar, and maple syrup. Bring the mixture to a boil, stirring contstantly. Allow to boil for 1 minute.
Remove the maple mixture from the heat and stir in the heavy cream. Add the chopped pecans and mix until combined. Pour the hot mixture over the partially baked crust, spreading it evenly.
Return the pan to the 350° oven, and bake for 25 to 30 minutes. The bars are done when the filling is bubbly, and the center is set when the pan is gently shaken. Let cool for at least 1 hour.
Remove the Maple Pecan Pie Bars from the pan by lifting the edges of the parchment paper. Using a large, sharp knife, cut into 9 larger squares or 16 smaller. Store in an airtight container at room temperature for up to a week.