Preheat oven to 350°F and prepare a square pan (9x9 or 8x8) with parchment paper.
Add cookie butter into a bowl and mix with a handheld or stand mixer for 2-3 minutes on medium speed.
1 cup cookie butter
Tumble in brown sugar and continue mixing.
1/2 cup light brown sugar
Add vanilla and egg. Continue mixing on medium speed. Scrape bowl when necessary with spatula.
2 tsp vanilla, 2 eggs
Mix the molasses in on low speed, it will be smooth but sort of oily texture. See video for exact visuals. Turn mixer off.
1/4 cup molasses
Add in flour and cinnamon. Mix on low speed until just combined. The dough will be thick.
1 cup + 2 tbsp all-purpose flour, 2 tsp cinnamon
Tumble in chocolate chunks and fold in with a wooden spoon.
1/2 cup chocolate chunks
Scrape the batter into the prepared pan and press it down into an even layer. Bake for 28-30 minutes. If you'd like to add extra chocolate chunks after baking to get that nice melted look, do it immediately after removing it from the oven.
Enjoy!