In a medium bowl, combine the flour & baking powder. Set aside.
In a large bowl, cream the room temp butter with the brown sugar until light & fluffy. Add the vanilla extract and maple syrup & beat until thoroughly combined.
Next, add the brown butter & and caster sugar; beat until fully incorporated. Add the egg & egg yolk, beating until homogenous.
Add the flour mixture into the butter mixture & beat until just incorporated. Then, using a spatula, carefully fold the pecans & chocolate chunks into the mix.
Wrap the bowl in cling film & leave to chill in the fridge for at least half an hour, ideally an hour.
Preheat oven to 160°C & line two baking trays with parchment paper.
Scoop dough by the two & a half tablespoonful onto the trays & flatten slightly, leaving at least 2-inches in between each cookie.
Bake for 15ish-minutes, or until golden brown. Remove from the oven & allow to cool for 5-minutes on the baking tray before moving to a wire rack to cool completely.