• Adjust the oven rack to the lowest position. Preheat oven to 350°F.
• Line a 13x9-inch baking pan with 2 pieces of parchment paper big enough to cover the bottom and sides of the pan. The two pieces of parchment should be perpendicular to each other creating a sling with the extra hanging over the edges. Lightly spray the parchment with vegetable cooking spray. Set aside.

For the crust:

• In a medium mixing bowl, whisk together the flour, sugar and salt. Add the melted butter and stir with a rubber spatula until a dough forms and no dry flour remains. The dough should hold together when pinched or squeezed. Distribute the crust dough evenly over the bottom of the prepared baking pan. Gently press and smooth the dough evenly using your fingers and palms. Scatter 1 cup of the chocolate chips evenly over the dough. Set aside.

For the topping:

• To toast the pecans, spread the nuts in a single layer on a large, rimmed baking sheet lined. Bake in a preheated 350°F oven until slightly darkened, about 8 to 12 minutes. Stir the pecans halfway through to prevent burning. Set aside.
• In a large mixing bowl, whisk together the brown sugar, syrup, melted butter, vanilla, salt and bourbon until smooth. Add the toasted pecans and fold together using a spatula until all nuts are evenly coated. Spoon the topping over the crust and chocolate chips. Gently spread the topping into the corners of the pan but don’t worry if there are bare patches. The topping will spread a little as it bakes. Bake for 25 to 30 minutes or until the topping is bubbling across the entire surface. Remove from the oven and top with the remaining chocolate chips.
• Cool completely in the pan, then sprinkle with the sea salt, if using. Using the parchment overhang, remove the bars from the pan and transfer to a cutting board. Cut into 24 bars.