Line a 9x9-inch baking dish with parchment paper, leaving some overhang on the sides for easy removal.
In a large mixing bowl, beat the softened unsalted butter or vegan butter together with the packed light brown sugar until light and fluffy (about 2-3 minutes).
Mix in the tablespoon of vanilla extract until well combined.
Gradually add the all-purpose flour and a pinch of salt (if using) to the butter-sugar mixture. Mix until just combined.
Gently fold in the chocolate chips or chunks, reserving 2 tablespoons for topping.
Transfer the cookie dough mixture into the prepared baking dish. Press it into an even layer.
Cover the dish with plastic wrap and refrigerate for at least 30 minutes to firm up the bars.
While the bars are chilling, prepare your hot fudge (homemade or store-bought).
Once chilled, remove the bars from the baking dish using the parchment paper overhang. Cut into squares, drizzle with hot fudge, and sprinkle with reserved chocolate chips.
