These Chocolate Chip Cookie Bars make that tradition especially easy. Soft, chewy, and filled with chocolate chips, they're mixed in one bowl and baked in a 9-inch square pan-no chilling, scooping, or baking multiple batches. I like to finish them with a drizzle of melted chocolate, but they're every bit as good straight from the pan.

And if you love cookie bars, try our favorite chewy oatmeal chocolate chip cookie bars too!

Stacked chocolate chip cookie bars drizzled in chocolate with more on a plate in the background.

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Back-to-school season has always made me think of cookies. At our house, they were the kind of after-school treat you could grab before heading outside to squeeze a little more summer from the afternoon.

Two children playing in a summer backyard with chocolate chip cookie bars in their hands.

Recipe Overview

Tools Needed: Mixing bowl, whisk, spatula, and a square 9-inch baking pan
Prep Time: 10 minutes
Bake Time: 30-34 minutes
Total Time: About 45 minutes
Yield: 16 bars
Why I Love Them: One bowl, no chilling or scooping, and easy to slice and share.

This is a simple one-bowl cookie recipe you'll want to keep on repeat. Begin by preparing the baking pan: Preheat the oven to 350°F and line a 9-inch square baking pan with parchment paper or foil. If using foil, lightly grease it.

Melted butter, brown sugar, granulated sugar, eggs and vanilla whisked together in a glass bowl.

Step 1: In a large bowl, whisk together the melted butter, brown sugar, and granulated sugar. Stir in the eggs and vanilla until smooth.

Chocolate chip cookie batter mixed together in a glass bowl with a rubber spatula.

Step 2: Fold the flour, cornstarch, salt, and baking soda into the wet ingredients until almost combined. Add the chocolate chips and fold just until everything comes together.

A parchment lined square baking pan with dollops of cookie batter and an offset spatula for spreading.

Step 3: Dollop the dough into the prepared pan. Using an offset spatula, spread the cookie dough into an even layer.

Baked chocolate chip cookie bars cooling in a parchment lined square baking pan on a marble counter.

Step 4: Bake for 30 to 34 minutes, or until the edges are lightly golden and the center is just set and a toothpick inserted in the center comes out with only a few crumbs attached.

Let the cookie bars cool before removing them from the pan. If desired, drizzle melted chocolate over the top for a coffeeshop Vonnies touch, and let it set for a few minutes before cutting into squares.

Top view of cut chocolate chip cookie bars on a white marble surface.

Recipe Notes

For soft, chewy bars: Bake just until the edges are lightly golden and the center is set. Avoid overbaking; the bars will continue to set as they cool.
Chocolate: Semi-sweet chocolate chips are my favorite, but milk, dark, or a combination also works.
Chocolate drizzle: This is optional, but delicious. Let the bars cool before drizzling them with melted chocolate.
Storage: Store in an airtight container at room temperature for 3 to 4 days, or freeze for up to 3 months.

Why I Call These Vonnies

The inspiration for these cookie bars came from a visit to Well & Good Coffee House near Portland, Oregon. The coffee was delicious, but it was the chocolate chip cookie bar beside it that I remembered.

They called them "Vonnies." I never did learn where the name came from, but after enjoying one with coffee, I came home determined to make my own version. This is the recipe I've been baking ever since.

Coffeeshop sign for original Vonnies at Well and Good coffee shop.

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