I Tried Cook’s Illustrated’s “Genius” Blondie Recipe, and Now I Understand the Hype

Blondies — like their chocolatey cousins, brownies — are tricky to get right. When done correctly, they’re delightfully chewy bars with a warm butterscotch flavor. But all too often they’re nothing more than a bar cookie knock-off. I decided an epic showdown would be the best way to find this unicorn, but first I had to select the contestants.

Luckily for me, Kitchn Tools Editor, Riddley Gemperlein-Schirm, had a strong opinion, claiming Cook’s Illustrated’s blondies were the best she’d ever had (plus, Food52 named them a “Genius Recipe.”) If there’s anyone I trust to put in the work to make a good blondie, it’s Cook’s Illustrated, with its meticulous, detailed, and scientific approach to recipes. Plus the recipe looked unique, in that it called for white chocolate and melted butter (vs. browned butter). Would this still provide the deep, butterscotch flavor I was looking for? I had to find out.

Get the recipe: Cook’s Illustrated’s Blondies

You’ll start by toasting nuts — either pecan or walnut halves (I tested with walnuts)— in a 350°F oven. Once the nuts are golden and fragrant, remove them from the oven, cool, then coarsely chop. Meanwhile, prepare a 9×13-inch baking pan by lining all sides with aluminum foil, then greasing it with butter or oil. I used a quick spritz of nonstick cooking spray.

Whisk all-purpose flour, baking powder, and table salt together until combined. In a separate bowl, whisk melted and cooled unsalted butter and light brown sugar together, then add a pair of eggs and vanilla extract. Whisk again until the mixture is smooth and combined. Fold the flour mixture into the wet ingredients with a spatula, stirring just until combined. Add the mix-ins — I used an equal amount of white chocolate and semi-sweet chocolate chips.

Transfer the batter into the pan, making sure to spread the mixture to the edges and smooth the top. Bake until the bars are light golden and the top is shiny and crackly, but do not over-bake. Cool the blondies completely in the pan on a wire rack, then use the foil lining to remove the bars from the pan to cut and serve.

Sometimes the perfect recipe is also the simplest. This no-fuss recipe delivers on every checkpoint on my list. The bars were rich, dense, and chewy, with an aroma of butterscotch and vanilla. They weren’t simply square-shaped chocolate chip cookies — they were something completely their own.

This recipe calls for melted and cooled unsalted butter, rather than going the extra step of browning the butter or softening it for creaming. This both streamlined the steps and also gave the bars the pure buttery flavor that is essential to blondies. The touch of baking powder added lift, and the addition of table salt created a balanced flavor.

Pecans and walnuts were both listed as mix-in options on the ingredient list, and I chose to bake the bars with walnuts. As it turns out, the buttery morsels of chopped, toasted walnuts added much more to the classic blondie flavor than the pecans did in the other recipes I tried. Also, I’m now of the opinion that blondies must include white chocolate chips. They practically melt into the background, boosting the vanilla and butterscotch notes of the blondies without competing for attention like darker chocolate does. But if you don’t want to go all in just yet, use equal parts white chocolate chips and semi-sweet chips.

1. Melt the butter, but don’t brown it. Simple melted butter supports a rich butterscotch flavor and chewy texture more than brown butter does. Melt the butter slowly in the microwave or over low heat on the stovetop to retain the butter’s water content, and let it cool before using so that it doesn’t scramble the eggs.
2. Opt for walnuts, and don’t forget to toast them. While I usually prefer pecans, the buttery bites of walnuts are the perfect mix-in for butterscotch blondies. Amplify the flavor of the nuts by toasting them first, making sure to chop after toasting so that the small bits of nuts don’t burn in the oven.
3. White chocolate is the surprising star. Even if you don’t love white chocolate, include it here! Too much dark or semi-sweet chocolate can overwhelm the butterscotch flavor of the blondies, while white chocolate practically melts into the bars, highlighting the buttery vanilla flavor notes.

Rating: 10/10

Have you ever made Cook’s Illustrated’s Blondies? Tell us what you thought!