Gooey Chocolate Chip Cookie Bars – Thick, Buttery & Packed with Melty Chocolate

These Gooey Chocolate Chip Cookie Bars deliver everything people love about classic American chocolate chip cookies—buttery brown-sugar flavor, golden chewy edges, a soft gooey center, and plenty of melted chocolate—without scooping or baking multiple batches.

The secret is slightly underbaking the center and using a combination of brown sugar, an extra egg yolk, and plenty of chocolate chunks. The bars continue to set as they cool, leaving the middle rich and soft instead of dry or cakey.

Serve them at room temperature for a chewy bakery-style treat, or warm a square and top it with vanilla ice cream for an easy crowd-pleasing dessert.

Ingredients

For the Cookie Bars

• 1 cup (2 sticks) unsalted butter, melted and slightly cooled
• 1½ cups packed light brown sugar
• ½ cup granulated sugar
• 2 large eggs, room temperature
• 1 large egg yolk
• 2 teaspoons pure vanilla extract
• 2¾ cups all-purpose flour
• 1 tablespoon cornstarch
• 1 teaspoon baking soda
• ¾ teaspoon kosher salt
• 1½ cups semisweet chocolate chips
• 1 cup roughly chopped semisweet or dark chocolate

For the Top

• ½ cup additional chocolate chunks or chips
• Flaky sea salt, optional

How to Make Gooey Chocolate Chip Cookie Bars

Step 1 – Prepare the Pan

Preheat the oven to 350°F (175°C).

Line a 9×13-inch metal baking pan with parchment paper, leaving enough overhang on the sides to lift the bars out later.

Lightly grease the parchment.

Step 2 – Combine Butter & Sugars

In a large bowl, whisk the melted butter, brown sugar, and granulated sugar until smooth and glossy.

Let the butter cool slightly before mixing so it doesn't scramble the eggs.

Step 3 – Add the Eggs

Whisk in the eggs one at a time.

Add the extra egg yolk and vanilla.

Whisk until the mixture looks thick, smooth, and well combined.

The extra yolk adds richness and helps create that soft, chewy center.

Step 4 – Mix the Dry Ingredients

In a separate bowl, whisk together:

• Flour
• Cornstarch
• Baking soda
• Salt

Cornstarch helps keep the bars soft and tender rather than overly crisp.

Step 5 – Make the Dough

Add the dry ingredients to the butter mixture.

Fold gently with a spatula until just a few streaks of flour remain.

Don't overmix.

Step 6 – Add the Chocolate

Fold in the chocolate chips and chopped chocolate.

Using both creates better texture: chips hold their shape while chopped chocolate produces irregular pools of melted chocolate throughout the bars.

Bake the Cookie Bars

Step 7 – Spread the Dough

Transfer the thick cookie dough to the prepared pan.

Press and spread it evenly into the corners.

Scatter the additional chocolate pieces over the surface and gently press them into the dough.

Step 8 – Bake

Bake for approximately 23–28 minutes.

The edges should be golden and set, while the center should still look slightly soft and underdone.

A toothpick inserted near the center should come out with moist crumbs.

Don't wait for it to come out completely clean.

Step 9 – Add Flaky Sea Salt

Immediately after removing the pan from the oven, sprinkle the warm surface lightly with flaky sea salt if desired.

The salty finish balances the brown sugar and chocolate beautifully.

Cool & Slice

Let the bars cool in the pan for at least 1 hour.

They'll continue setting as they cool.

For very gooey bars, slice while they're still slightly warm.

For clean bakery-style squares, let them cool completely before lifting the slab from the pan.

Cut into 20–24 bars.

Chef's Tips for Perfect Gooey Cookie Bars

• Measure the flour carefully. Too much flour is one of the easiest ways to turn gooey cookie bars dry.
• Melted butter creates a dense, chewy texture.
• Brown sugar provides more moisture and caramel flavor than granulated sugar alone.
• The extra egg yolk adds richness without making the bars cakey.
• Don't overmix after adding the flour.
• Use a metal baking pan for more predictable baking and nicely browned edges.
• Use both chocolate chips and chopped chocolate for better chocolate distribution.
• Reserve some chocolate for the top.
• Slightly underbake the center. This is the most important trick.
• Remember that the bars continue cooking from residual heat after leaving the oven.
• Don't judge the texture while they're piping hot—they need time to set.
• A little flaky sea salt makes the chocolate flavor pop.

The Secret to a Gooey Center

The biggest secret is simple:

Take them out before they look completely finished.

The edges should be golden and firm, but the center should still appear softer and slightly glossy.

Because the pan remains hot after leaving the oven, residual heat continues setting the middle.

If you wait until the center looks completely baked while it's still in the oven, you'll usually end up with firmer, drier bars after cooling.

How to Get Big Melted Chocolate Pools

Use a chopped chocolate bar in addition to regular chocolate chips.

Chop the chocolate into uneven pieces—some small, some fairly large.

The smaller pieces melt into the cookie dough, while the large chunks create dramatic molten pockets.

As soon as the bars leave the oven, you can gently press a few additional chocolate chunks into the warm surface. They'll soften naturally without disappearing into the dough.

Delicious Variations

Salted Caramel Cookie Bars

Drizzle cooled bars with salted caramel and finish with flaky sea salt.

Chocolate Chip Pecan Bars

Fold 1 cup toasted chopped pecans into the dough.

Oreo Chocolate Chip Cookie Bars

Add roughly chopped Oreo cookies along with the chocolate.

Peanut Butter Chocolate Chip Bars

Swirl ½ cup creamy peanut butter through the dough before baking.

S'mores Cookie Bars

Add mini marshmallows, chopped chocolate, and broken graham crackers.

Triple Chocolate Cookie Bars

Use a combination of milk, semisweet, and dark chocolate chunks.

Brown Butter Chocolate Chip Bars

Brown the butter first for deeper nutty, toffee-like flavor. Let it cool slightly before continuing with the recipe.

For Extra-Gooey Dessert Bars

If you're serving these warm as a plated dessert, bake toward the shorter end of the recommended time.

Let them rest for about 20–30 minutes, then scoop or cut a thick warm portion onto a plate.

Top with:

• Vanilla bean ice cream
• Warm chocolate sauce
• Salted caramel
• Extra chocolate chunks
• A tiny pinch of flaky sea salt

The warm center should be soft and gooey but still baked enough to hold together, while the ice cream slowly melts over the top.

How to Get Clean Bakery-Style Squares

Cool the cookie bars completely.

Lift the entire slab from the pan using the parchment overhang.

Use a large, sharp knife and wipe it clean between cuts.

For exceptionally sharp edges, chill the cooled bars for about 20–30 minutes before slicing.

Let them return to room temperature before serving for the best chewy texture.

What to Serve With

• Cold milk
• Hot coffee
• Espresso
• Vanilla ice cream
• Chocolate ice cream
• Salted caramel ice cream
• Fresh strawberries
• Whipped cream

For the classic American dessert experience, warm one cookie bar for about 10–15 seconds and serve it with a scoop of vanilla ice cream.

Make-Ahead Tips

These bars are excellent for making ahead.

Bake them 1 day before serving, cool completely, and keep them tightly covered at room temperature.

You can also prepare the cookie dough ahead and refrigerate it overnight. Let it soften slightly before pressing it evenly into the pan.

Storage

Room Temperature

Store completely cooled bars in an airtight container for up to 4–5 days.

Place parchment between layers.

Refrigerator

Refrigerate for up to 1 week.

Let them return to room temperature or warm them briefly before serving for a softer texture.

Freezer

Wrap individual bars tightly and place them in a freezer-safe container.

Freeze for up to 3 months.

Thaw at room temperature or microwave briefly until soft and slightly warm.

Notes

• Semisweet chocolate is an excellent all-around choice because it balances the sweet cookie base without becoming bitter.
• Dark brown sugar can replace light brown sugar for an even stronger molasses and caramel flavor.
• Don't overbake these bars if you're aiming for the signature gooey center.
• The texture changes as they cool: warm bars are soft and gooey, while completely cooled bars become dense and chewy.
• Gooey Chocolate Chip Cookie Bars are perfect for birthday parties, bake sales, potlucks, game day, holiday cookie trays, family gatherings, after-school treats, or anytime you're craving classic chocolate chip cookies without baking individual batches.