Line your baking pan with parchment paper, leaving an overhang for easy removal, and preheat your oven to 175°C (350°F).
In a mixing bowl, combine the flour, brown sugar, and salt. Stir until evenly mixed.
Add the cold, cubed butter to the dry mixture. Use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs.
Press this crumbly mixture evenly into the prepared pan, creating a smooth, compact crust. Bake for about 15 minutes until lightly golden around the edges.
While the crust bakes, toast the pecans until fragrant—about 8 minutes at 175°C (350°F)—then chop or leave whole, depending on your preference.
Once the crust is baked and slightly cooled, pour the maple syrup evenly over the crust. This will create a sticky, sweet base for the pecans to cling to.
Spread the toasted pecans over the maple layer, pressing them gently into the syrup so they adhere well.
In a small saucepan, melt the remaining butter with the powdered sugar to make a smooth glaze. Once warmed and combined, pour this over the pecans, spreading evenly.
Sprinkle a pinch of flaky sea salt over the top, if using, to enhance the caramel and maple flavors.
Let the bars cool completely in the pan, allowing the glaze to set and the flavors to meld. Once cooled, lift out using the parchment overhang and cut into squares.
Serve at room temperature to enjoy the crispy crust, sticky glaze, and crunchy pecans in every delicious bite.
