Prep the pan and oven: Heat your oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment, leaving an overhang for easy lifting. Lightly grease the sides.

Melt the butter: Melt unsalted butter until just liquid. Let it cool for 5 minutes so it doesn’t scramble the eggs.

Mix the sugars and butter: In a large bowl, whisk melted butter with brown sugar and granulated sugar until glossy and well combined. This helps create that chewy texture.

Add eggs and vanilla: Whisk in eggs one at a time, then add vanilla extract. Mix until smooth and slightly thick.

Combine dry ingredients: In a separate bowl, whisk flour, baking soda, and salt. Fold the dry mixture into the wet ingredients just until no dry streaks remain.

Stir in chocolate: Fold in chocolate chips or chunks. Save a small handful to sprinkle on top for a bakery-style look.

Spread the dough: Scrape the thick dough into the prepared pan. Use a spatula or damp fingertips to press it evenly into the corners. Sprinkle on reserved chocolate.

Bake: Bake for 22–28 minutes, or until the edges are set and golden and the center looks slightly underbaked but not jiggly. A toothpick should come out with a few moist crumbs, not wet batter.

Cool and slice: Cool in the pan on a rack for at least 30–45 minutes. Lift out using the parchment and cut into squares or bars. For cleaner cuts, chill for 20 minutes before slicing.

Finish (optional): Sprinkle with flaky sea salt while warm to balance the sweetness.