First, I preheated my oven to 350 °F (180 °C) and buttered the 8×8-inch pan. I then lined it with parchment paper, letting the paper come up on two sides so I could easily lift the bars out later.
In a large mixing bowl I whisked together the melted butter, dark brown sugar, dark maple syrup, the egg, vanilla extract, and salt until smooth and shiny. This wet base is what gives the bars their rich, chewy texture.
In a separate small bowl I whisked the flour with the baking soda, then folded this dry mixture into the wet until just combined. After that, I folded in the toasted chopped pecans to distribute them evenly.
I poured the batter into the prepared pan and baked it for about 30-35 minutes, until the edges were set and the centre still had a little jiggle. The gentler bake ensures chewiness rather than dryness.
After baking, I let the pan sit for ten minutes before transferring the bars to a wire rack to cool completely. This resting time helps the texture set properly.