Preheat the oven to 350°F (175°C).
Spread the measured all-purpose flour evenly on a large baking sheet and bake for 5–10 minutes to heat-treat it; this kills any lingering bacteria. Let the flour cool completely before using.
Line an 8x8-inch baking pan with aluminum foil and lightly spray or grease the foil; set aside.
In a large mixing bowl, beat the softened butter and packed light brown sugar with a whisk or electric mixer until soft and fluffy, about 3 minutes. Beat in the vanilla extract.
Stir the cooled, toasted flour and the pinch of salt (if using) into the butter mixture until fully combined and a dough forms.
Fold in the semi-sweet chocolate chips or chunks, reserving about 2 tablespoons to press on top after pressing the dough into the pan.
Turn the dough out into the prepared pan and press it firmly and evenly with a spatula.
Evenly press the reserved 2 tablespoons of chocolate chips into the top of the dough for decoration.
Refrigerate or freeze the pan for at least 2 hours (or overnight) to set. Bars slice more easily when chilled; if frozen, let slices sit at room temperature about 10 minutes before serving if desired.
Optionally drizzle with warm hot fudge, chocolate syrup, or salted caramel before serving.