Instructions

• Preheat the oven to 350 degrees F. Line an 8x8-inch baking pan with parchment paper or foil and spray the lining well with non-stick baking spray. Set the prepared pan aside.
• In the bowl of a stand mixer fitted with the paddle attachment, place 1 cup creamy cookie butter. Beat on medium-high until smooth and creamy, about 2 minutes.
• Add 1/2 cup light brown sugar (packed), 1/3 cup granulated sugar, and 1 tablespoon vanilla extract. Beat on medium for 2 to 3 minutes, stopping once or twice to scrape down the sides of the bowl.
• Add 1 large egg plus 1 egg yolk and beat until incorporated. Then add 1/4 cup molasses and beat just until combined.
• Turn the mixer off. Add 1 cup plus 1 tablespoon all-purpose flour (measured without packing), 1 1/2 teaspoons ground cinnamon, and 1/2 teaspoon salt. Turn the mixer to low and mix only until just combined, about a minute—do not overmix. The batter will be very thick.
• Fold in the 4 ounces semi-sweet chocolate chunks with a spatula, mixing just until evenly distributed.
• Scrape the batter into the prepared pan and press it down into an even layer.
• Bake for 30 to 32 minutes, until the edges are set and the center is just slightly soft.
• Remove the pan from the oven. Immediately sprinkle the reserved 2 ounces semi-sweet chocolate chunks evenly over the hot bars so they soften/melt; if desired, press them lightly into the surface. Sprinkle flaky sea salt over the top to taste.
• Transfer the pan to a cooling rack and cool completely in the pan for at least 1 hour before slicing into bars.