With these double chocolate chip cookie bars, I set out to make a bar cookie that hits all the right notes: chewy, dense, chocolatey, and most of all, easy. Made in one bowl with melted butter and oil, these rich treats come together quickly, bake in 20 minutes, and slice perfectly once cooled.
I wanted these double chocolate chip cookie bars to share the best parts of a rich chocolate cookie - chewy edges, dense center, and melty chocolate throughout - but in an easy bar form.
The dough comes together in one bowl with melted butter and a bit of oil, so there's no mixer, no fuss, and no pile of extra dishes! These double chocolate bars bake quickly, slice neatly, and have the perfect balance of soft and chewy.
I knew I couldn't just press a double chocolate cookie recipe into a pan with the results I was seeking. I tested a few versions before landing on this one.
I started with all melted butter, but swapped in a bit of oil to keep the bars from drying out over time. I omitted leavening and removed the egg whites, using only the yolks to keep a dense texture and avoid cakiness.
These bars are dense, chocolatey, and reliably sliceable - perfect for dessert plates, a casual snack, or a quick treat straight from the pan.
For more chewy chocolate treats, try my Italian chocolate hazelnut sandwich cookies, brownie blondie bars, or chocolate coffee mascarpone sandwich cookies.
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Ingredients
* See recipe card for full list of ingredients and quantities.
Unsalted butter - Unsalted butter gives you full control over the salt. Melted butter makes the bars chewy and dense, and it means you can stir everything together by hand. No mixer required!
Vegetable oil - Without oil, the bars tasted great but dried out quickly. A little oil keeps them soft and moist for days.
Brown sugar - Extra brown sugar adds caramel flavor and chew. Skip coarse organic brown sugar - it won't dissolve well and can leave the bars grainy.
Granulated sugar - A bit of granulated sugar gives the bars a crisp exterior and glossy top.
Egg yolks - Using egg yolks rather than whole eggs adds additional flavor and richness without as much moisture, creating a fudgier texture. I know it's a bit of a pain to separate eggs, but the effort is worth the outcome.
Egg yolks - Egg yolks add richness without extra moisture, creating a fudgy texture. I know separating eggs is annoying and takes a few extra minutes, but it's worth it!
Vanilla extract - Use pure vanilla extract, or swap 1:1 with vanilla paste if preferred.
Kosher salt - I use Diamond Crystal kosher salt in my recipes.
All-purpose flour - I use a digital scale to measure most ingredients, especially flour. Without one, fluff the flour, spoon it into the measuring cup, and level it with a knife.
Cocoa powder - Either Dutch process or natural cocoa works here since there's no leavening. Natural cocoa gives a warmer color and fruity flavor; Dutch process gives a darker look and bolder chocolate taste.
Espresso powder - Espresso powder (optional) deepens the chocolate flavor.
Chocolate chips - I use semisweet chips, but any chocolate you love - chips or chunks - will work.
Instructions
These photos provide visual cues. Find the detailed instructions in the recipe card.
Line an 8-inch (20 cm) square metal baking pan with parchment paper, leaving an overhang on two sides for easy removal.
In a large microwave safe bowl, melt butter. Add oil, brown sugar and granulated sugar.
Mix butter, oil and sugars until well combined. It's OK if the mixture is a bit lumpy.
Add egg yolks, vanilla and salt.
Mix until eggs are fully incorporated.
In a separate bowl, sift together the flour, cocoa powder, and espresso powder (if using).
Whisk dry ingredients together.
Add dry mixture to wet ingredients.
Stir dry ingredients into wet until just combined.
Add chocolate chips or chunks.
Fold in the chocolate chips.
Scoop dough into parchment lined pan.
Press dough into an even layer, making sure it extends to corners of pan.
Bake in oven for 20-22 minutes, until the edges are set and the middle is just barely firm when pressed.
Hint: For best results (and neat slices), wait until the bars are cool before cutting into pieces. They'll have a denser, fudgier mouthfeel if allowed to cool first, and the bars will be easier to slice cleanly.
Equipment
8-inch square metal pan - For perfectly baked bar cookies, I use and recommend the 8 x 8 inch square pan made by USA Pan. It's my go-to for its straight, clean edges and even heating.
A note on pan material: Glass and metal pans conduct heat very differently.
- Metal pans: Heat up quickly and create light, crispy edges.
- Glass pans: Take longer to heat up and retain heat longer, which can lead to overbaked edges.
If you only have a glass pan, you may need to experiment by lowering the oven temperature by 25°F and extending the bake time by 5-10 minutes.
For more on how different materials affect your baking, see King Arthur Baking's guide on choosing the right bakeware.
Variations
Other baking chip flavors - to change these from chocolate chocolate chip cookie bars, substitute the same amount of white chocolate, butterscotch, peppermint or peanut butter baking chips.
Orange zest - Add the freshly grated zest of one orange to the dough when adding the eggs.
Nuts - Add about ¼ cup (25-30 grams) of toasted, chopped nuts when adding the chocolate chips. Try hazelnuts, pecans, walnuts or almonds.
Frequently asked questions
- These bars have less fat than typical brownies, which gives them chewy edges and a firmer, less gooey center.
- Using only egg yolks instead of whole eggs creates a denser, more cookie-like structure than a brownie.
- A more moderate amount of cocoa powder delivers rich chocolate flavor without creating the fudgy texture of a brownie.
If you're wondering what to make with 2 leftover egg whites, try one of these recipes:
- Kokosmakronen (German coconut macaroons): crisp and crunchy on the outside, moist and chewy inside - and no whipping egg whites required in my version.
- Baci di Alassio: decadent chocolate hazelnut cookies sandwiched with silky dark chocolate ganache.
Love this recipe? Please leave a comment and star rating. ★★★★★ Your feedback, suggestions, and adaptations are very helpful to other bakers!
📖 Recipe
Double Chocolate Chip Cookie Bars
INGREDIENTS
- 113 grams unsalted butter
- 150 grams brown sugar, light
- 25 grams granulated sugar
- 2 large egg yolks
- 7.5 mL vanilla extract
- ¾ teaspoon kosher salt, Diamond Crystal
- 135 grams all purpose flour
- 25 grams cocoa powder, Dutch or natural, sifted
- ½ teaspoon espresso powder, optional, enhances chocolate depth
- 85 grams chocolate chips, semisweet
INSTRUCTIONS
- Place rack in center of oven and preheat to 350° Fahrenheit (177° Celsius, Gas mark 4)
- Line an 8-inch (20 cm) square metal baking pan with parchment paper, leaving an overhang on two sides for easy removal.
- Melt the butter in a microwave-safe bowl or small saucepan. Add both sugars and whisk until smooth and glossy.113 grams unsalted butter, 150 grams brown sugar, 25 grams granulated sugar
- Add egg yolks, vanilla, and salt. Whisk until fully combined.2 large egg yolks, 7.5 mL vanilla extract, ¾ teaspoon kosher salt
- In a separate bowl, sift together the flour, cocoa powder, and espresso powder (if using).135 grams all purpose flour, ½ teaspoon espresso powder, 25 grams cocoa powder
- Stir dry ingredients into wet until just combined. Fold in the chocolate chips or chunks.85 grams chocolate chips
- If your dough is still warm, it will most likely be pourable. If so, pour it into the pan and spread evenly.If it has cooled and become thicker, scoop it into the pan in spoonfuls and press it into an even layer.
- Bake for 20-22 minutes. The edges should be set, the top shiny, and the center should not jiggle.
- Cool completely in the pan on a wire rack. Use the parchment overhang to lift out cooled bars and slice into squares.
EQUIPMENT
NOTES
- If you make the dough quickly, the melted butter will still be warm, and the dough will have a thinner consistency that can be poured into the pan.
- If you make the dough slowly (or melt the butter over low heat), the dough will cool and firm up. You'll need to scoop and press it into the pan.
- I baked batches with both dough consistencies with no noticeable change to the final results.
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