Chewy, buttery butterscotch bars studded with sweet chips and a hint of vanilla. Simple to make in one bowl and perfect for bake sales, picnics, or anytime you need a crowd-pleasing treat.
Preheat oven to 350°F. Line a 9x13 inch baking pan with parchment, leaving overhang, and lightly grease.
In a large bowl, whisk melted butter and brown sugar until smooth and slightly thick. Let sit 2 minutes to cool.
Whisk in eggs and vanilla until glossy and well combined.
In a separate bowl, whisk flour, baking powder, and fine sea salt. Add dry ingredients to wet and stir just until no dry streaks remain.
Fold in butterscotch chips and pecans (if using). Spread batter evenly in the prepared pan. Sprinkle flaky sea salt on top if desired.
Bake 22 to 26 minutes, until the edges are golden and a toothpick inserted near the center comes out with a few moist crumbs.
Cool completely in the pan on a rack. Lift out using the parchment and cut into 16 bars.
Notes
For thicker, ultra-chewy bars, bake in a 9x9 inch pan and add 3 to 5 minutes to the baking time. Store in an airtight container at room temperature for up to 4 days or freeze up to 2 months.