Cook's Illustrated's Blondies

Test Kitchen-Approved

Author Notes: These are the blondies you'll become known for. A few notes: The key to their flavor is the heavy dose of vanilla -- don't skimp, and don't use artificial extract. Err on the side of under-baking. These are delicious cold from the freezer or fridge (and easiest to slice that way). Adapted slightly from Cook's Illustrated (July 2005).Genius Recipes

Makes: 36
Prep time: 30 min
Cook time: 45 min


  • 1 cup pecans or walnuts (4 ounces)
  • 1 1/2 cups unbleached all-purpose flour (7 1/2 ounces)
  • 1 teaspoon baking powder
  • 1/2 teaspoon table salt
  • 12 tablespoons unsalted butter ( 1 1/2 sticks), melted and cooled
  • 1 1/2 cups packed light brown sugar (10 1/2 ounces)
  • 2 large eggs, lightly beaten
  • 4 teaspoons vanilla extract
  • 6 ounces white chocolate chips (1 cup) or chopped bar, or 3 ounces each white chocolate and semisweet chocolate chips
In This Recipe


  1. Adjust oven rack to middle position; heat oven to 350° F. Spread nuts on large rimmed baking sheet and bake until deep golden brown, 10 to 15 minutes. Transfer nuts to cutting board to cool; chop coarsely and set aside.
  2. While nuts toast, line a 13 by 9-inch baking pan with foil, leaving enough overhang to help you lift the blondies from the pan when they're done. [Here are Cook's Illustrated's measurements, but you can just wing it: Cut 18-inch length foil and fold lengthwise to 8-inch width. Fit foil into length of 13 by 9-inch baking pan, pushing it into corners and up sides of pan; allow excess to overhang pan edges. Cut 14-inch length foil and fit into width of baking pan in same manner, perpendicular to first sheet (if using extra-wide foil, fold second sheet lengthwise to 12-inch width).] Grease foil-lined pan with butter or oil.
  3. Whisk flour, baking powder, and salt together in medium bowl; set aside.
  4. Whisk melted butter and brown sugar together in medium bowl until combined. Add eggs and vanilla and mix well. Using rubber spatula, fold dry ingredients into egg mixture until just combined; do not overmix. Fold in chocolate and nuts and turn batter into prepared pan, smoothing top with rubber spatula.
  5. Bake until top is shiny, cracked, and light golden brown, 22 to 25 minutes; do not overbake. Cool on wire rack to room temperature. Remove bars from pan by lifting foil overhang and transfer to cutting board. Cut into 2-inch squares and serve.

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Reviews (64) Questions (1)

64 Reviews

Emma February 26, 2019
These were sooo good. i didn't have any trouble with underdoneness, as others did. Browned the butter, cut the sugar by 25%, and used mostly white whole wheat (what I had). I mixed in pecans and a mix of chocolate chips and chocolate covered sunflower seeds--perfect!!
Gina H. February 7, 2019
Made these on a cold snowy day and they turned out wonderful. I followed the recipe as directed, mostly. At the suggestion of others I browned my butter. I don't like white chocolate so I used a mix of what I had on hand - chocolate chips and heath bar. I also added walnuts. After reading the reviews I was concerned about the cooking time but mine cooked in 25 min. I would wait about 5 min to remove the foil sling to the rack. It takes them at least 30 min to cool and not be gooey. Great consistency.
Baker B. January 20, 2019
Agree with fishinwindow. Maybe had to do with pan used, I used a Pyrex 13x9. Perhaps metal would be better. I cooked 26 minutes and they were underdone. Good flavor.
fishinwidow December 14, 2018
I made these recently and cooked them for 23 min. They were WAY underdone. Raw and greasy. I'd like to try again because the flavor was delicious (I browned the butter), but next time I will definitely bake them for at least 30 min. Before removing them from the oven, make sure they're well cracked on top and browned around the edges.
BarbaraM December 12, 2018
I've been making these with white chocolate chips, chopped pistachios, bits of marzipan and dusted with liquorice powder for a scandi twist, and have been getting rave reviews.
BarbaraM December 12, 2018
Oh and baked them as cookies!
Luciana October 18, 2018
I'm amazed a CI recipe misses the step of browning the butter in these babies. That's the best part of blondies! Glad most of the commenters added that step. :0)
laurajg October 16, 2018
I upped the butter on these to a full cup, since some people said they were dry. I browned the butter before adding it to the sugar. I also used 7 ounces of ghiradelli dark chocolate chips, and omg these are delicious. One of my favorite blondie recipes ever.
morgan October 5, 2017
Made these with a few changes, I browned my butter, swapped in almonds cause that's what I had on hand and ran out of brown sugar so my sugar ratio ended up with 1 cup brown sugar, 1/4 white sugar and then the last 1/4 I used homemade caramel. The batter barely made it into the oven it was so good, however what came out supased it. My new go to Blondie recipe.
a June 14, 2017
Just made these using Bob's gluten free flour.
They came out great. I also added chopped dried cherries and cacao nibs in addition to the toasted pecans. I baked them in my toaster oven in a 12"×12" pan with non stick foil, no added spray, for exactly 22 minutes. I store them in the freezer separated by foil in a rubbermaid container.
JaniceB May 6, 2017
I took a cue from the brown butter blonde recip from this site and simply subbed that for the regular melted butter. Chopped my chocolate instead of chips. Seriously, the most amazingly delicious blondies ever. Brought them to work and my colleagues were devouring them.
Wendy April 30, 2017
Hmmm.....these were not what I was expecting. I followed the recipe as written. I was careful to not over-mix or over-bake. In fact, I pulled the blondies out of the oven at 21 minutes. I found these to be cakey in texture and rather bland in flavor - certainly not the butterscotchy flavor I usually aspire to. Oh well, its always good to see if there is something better out there. In this case, definitely not.
glutwin October 5, 2017
I had the exact same result! I was disappointed with the 'cake-y' aspect (I like any brownie to be 'moelleux'...somewhat moist with finished 'edge'. I found them on the 'bland' side as well. In short...Ditto the above!!
Änneken September 18, 2016
These are amazing! I just tried them and I love their pillowy-on-the-inside-crunchy-on-the-outside texture. I cut down the sugar to 7 oz instead of 10.5 oz and I am glad I did. They'll be my lunch desserts this week. Yumm!
Carol S. June 13, 2016
Made these today with dark brown sugar and half each good white and 70% chocolate chunks. I found the texture ok, but kind of bland. The white chocolate disappeared into the bar, leaving not enough chocolate taste. Used very good vanilla, too, and added just a tad extra salt, but still needed something......hmmmm.
KathMo June 3, 2016
Walnuts + Heath toffee bits + dark brown sugar = great cookies. I used parchment, too.
glutwin October 5, 2017
Now THAT sounds like it could be the 'ticket...Ratios SVP?! Pretty please...ex-pat Heath lover across the pond!!
Noreen F. March 24, 2016
I've made these many times, and turned blondie-haters into blondie-lovers with them!
Grace December 22, 2015
I have probably made these ten times now. The ease-to-wow ratio is pretty fantastic. I must have misplaced the magazine with the recipe - so thanks for posting this!
Oh - and yes, I always use a glass 13x9 pan, simply because it's what we have. I've found that Cooks' recipes are incredibly forgiving - so don't worry too much.
Leah B. November 5, 2015
Has anyone made this in a glass dish before? My options are 13x9 glass or 9x9 metal pan.
kim June 19, 2015
I love blondies since first eating them in Charleston, S.C., where they incorporate "Praline" into all kinds of scrumptious delights. I baked my version in 9" x 9" pan to get a rich, chewy texture & substituted a little over 5 ounces of finely ground & roasted hazelnuts along with about 2 1/2 oz. course chunks of Valrhone Ivoire Feves (left-over from making white chocolate shortcakes with strawberries and cream). It was phenomenal! This is a "Genius Recipe"! For my next batch, I'm want to try portioning the batter into individual silicone baking cups and freezing; Can you recommend the proper baking technique if the batter is frozen raw in standard muffin-size portions? Should I bake them frozen or thawed and make any adjustments to the temperature? Thanks!
Kara June 18, 2015
I've made these Blondies twice now and both times have been an absolute hit with all who have eaten them. I really like that these blondies are chewy on the inside but crunchy on the outside.
Beysh June 9, 2015
This recipe and technique are almost identical to the Blondies recipe in the second Silver Palate cookbook--including the large quantity of vanilla. Sprinkling a few extra chips on the top, along with a some flaky sea salt, takes them even a level higher.