• Preheat the oven to 350°F. Grease the bottom of an 8x8-inch pan and line it with parchment paper.

Toast the pecans (optional)

• Place pecans on a baking sheet and sprinkle with salt. Toast in the oven for 10-15 minutes, until the color begins to deepen. Set aside to cool.
  2 ½ cups chopped pecans, ¼ teaspoon kosher salt

Brown the butter

• Next, brown or heat your butter. Here is our step-by-step guide on how to brown butter. Heat the butter in a light-colored saucepan over medium heat, stirring constantly until the butter bubbles up and begins to smell nutty. Then, remove it from the heat and set aside to cool for about 5 minutes. 
  8 tablespoons unsalted butter

Brown butter shortbread crust

• Stir in vanilla extract to the brown butter mixture.
  6 tablespoons browned butter, 1 teaspoon vanilla extract
• In a bowl, combine the flour, salt, brown sugar, and whisk to combine until there are no clumps.
  1 ¼ cup flour , 6 tablespoons dark brown sugar , ½ teaspoon kosher salt
• Then, add in the brown butter and vanilla mixture. Use a fork to clump the mixture together. 
• Press the crust into a flat layer in a prepared pan. Bake for 15-20 minutes, until the crust is set and the edges are beginning to turn golden brown.

Filling

• While the crust is baking, make the filling. In a mixing bowl, whisk together the brown sugar, maple syrup, vanilla extract, kosher salt, optional bourbon, and cinnamon until smooth.
  ¾ cup + 2 tablespoons maple syrup, ½ cup dark brown sugar, 1 tablespoon vanilla extract, 1 tablespoon bourbon, ¾ teaspoon kosher salt, 1 teaspoon cinnamon
• Add in the two eggs. Whisk the mixture together again until totally smooth and combined, then sift in the flour. Finally, gently mix everything together until combined. 
  2 large eggs, 3 tablespoons all-purpose flour
• Now, fold in the pecan pecans and chocolate, reserving a few for the top of the bars. Make sure everything is well coated. Use a rubber or offset spatula to spread the filling over top of the cooked shortbread crust in an even layer, and top with the remaining chocolate and pecans if desired. 
  1 cup dark chocolate chips, 2 ½ cups toasted and salted pecans
• Bake for 37-42 minutes, or until the top is golden brown and puffed and looks dry and set, but springs back a little bit when touched. An instant-read thermometer should read around 200°F if inserted into the center.
• Allow the bars to cool in the pan for at least 2 hours, or until completely cooled so the bars can set up. You can transfer them to the fridge to speed up the process and for cleaner cuts!
• Cut into 9-16 pieces (your choice!) and enjoy! These would be great with whipped cream, a scoop of ice cream, or a drizzle of salted caramel!
• Store leftovers in an airtight container at room temperature for up to 4-5 days, or in the fridge for up to 7 days.To freeze, wrap tightly in plastic wrap, then aluminum foil, and place in the freezer for up to 3 months.