Unsalted butter simply gives you more precise control over the final seasoning.
Why Are My Cookie Bars Dry?
The most common cause is overbaking.
Cookie bars firm significantly as they cool, so waiting for the middle to look dry inside the oven usually means they have baked too long.
Using too much flour can also cause dryness, which is why weighing the flour in grams gives the most reliable result.
Make-Ahead Tips
The cookie dough can be prepared and pressed into the lined pan up to 24 hours ahead.
Cover tightly and refrigerate.
Bake directly from chilled, allowing an additional minute or two if needed.
You can also simply bake the entire recipe one day before serving.
Once completely cooled, keep the bars tightly covered at room temperature.
Storage
Room Temperature
Store the cooled cookie bars in an airtight container for up to 3 days.
Layer pieces of parchment paper between the bars if stacking.
Refrigerator
For longer storage, refrigerate for up to 5 days.
The chocolate and butter firm when chilled, so the bars will taste denser straight from the refrigerator.
Let them return to room temperature or warm briefly before serving.
Freezer
Wrap individual bars tightly and place them in a freezer-safe container or bag.
Freeze for up to 6 weeks.
Thaw at room temperature for approximately 1 hour.
How to Reheat Brown Butter Cookie Bars
If you love soft melted chocolate, reheating these bars briefly makes them taste remarkably close to freshly baked.
Microwave one bar for approximately 8–12 seconds.
For several pieces, arrange them on a baking sheet and warm at 300°F (150°C) for approximately 5–7 minutes.
Do not overheat them, or the centers can lose their fudgy texture.
What to Serve With Brown Butter Chocolate Chip Cookie Bars
These bars are rich enough to stand alone, but a few simple pairings work especially well:
- Cold whole milk
- Hot coffee
- Espresso
- Vanilla ice cream
- Salted caramel ice cream
- Fresh strawberries
- Fresh raspberries
- Lightly whipped cream
For an easy restaurant-style dessert, warm one large cookie bar for a few seconds and top it with vanilla ice cream and a tiny pinch of flaky sea salt.
Brown Butter Chocolate Chip Cookie Bars Recipe Card
Prep Time: 20 minutes
Cook Time: 18–22 minutes
Cooling Time: 1–2 hours
Total Time: About 1 hour 40 minutes
Yield: 9 large or 16 smaller bars
Pan: 8 x 8-inch metal baking pan
Oven: 350°F (175°C)
Ingredients
- ¾ cup (170g) unsalted butter
- ¾ cup (150g) packed light brown sugar
- ½ cup (100g) granulated sugar
- 1 large egg, room temperature
- 1 large egg yolk, room temperature
- 2 teaspoons vanilla extract
- 1¾ cups (210g) all-purpose flour
- 2 tablespoons (16g) full-fat milk powder, optional
- 1 tablespoon (8g) cornstarch
- ½ teaspoon instant coffee or espresso powder, optional
- ½ teaspoon baking powder
- ½ teaspoon fine salt
- 1¼ cups (210g) semisweet chocolate chunks, plus more for topping
- Flaky sea salt, optional
Instructions
- Preheat the oven to 350°F (175°C). Line an 8 x 8-inch metal pan with parchment paper.
- Brown the butter over medium heat until the milk solids become deep amber and smell nutty. Immediately transfer to a mixing bowl and cool for 10–15 minutes.
- Whisk the brown sugar and granulated sugar into the brown butter until glossy.
- Add the egg, yolk, and vanilla. Whisk vigorously for approximately 1 minute until thicker and slightly paler.
- Fold in the flour, milk powder, cornstarch, instant coffee, baking powder, and salt until a few flour streaks remain.
- Add the chocolate chunks and fold just until combined.
- Press evenly into the prepared pan and add extra chocolate chunks on top.
- Bake for 18–22 minutes, until the edges are set and golden but the center remains slightly soft.
- Cool completely in the pan before lifting out and slicing.
- Finish with flaky sea salt if desired.
Notes
For the best texture, do not judge these bars by whether a toothpick comes out completely clean. Moist crumbs are what you want.
An 8 x 8-inch metal pan produces the thickest, gooey center. A 9 x 9-inch pan produces thinner bars and may require slightly less baking time.
If you want those large bakery-style pools of melted chocolate visible on top, reserve a handful of chopped chocolate and press it into the surface just before baking.
And if there is one thing worth remembering from this entire recipe, it is this:
Take the bars out before they look completely finished...