Why This Recipe Works
Blondies are first cousins to both brownies and chocolate chip cookies. Although blondies are baked in a pan like brownies, the flavorings are similar to those in chocolate chip cookies—vanilla, butter, and brown sugar. They’re sometimes laced with nuts and chocolate chips or butterscotch chips. But even with these extras, blondies can be pretty bland, floury, and dry. We set out to fix the blondie so it would be chewy but not dense, sweet but not cloying, and loaded with nuts and chocolate.
We found that the key to chewy blondies was using melted, not creamed, butter because the creaming process incorporates too much air into the batter. For sweetening, light brown sugar lent the right amount of earthy, molasses flavor. And combined with a substantial amount of vanilla extract and salt (to sharpen the sweetness), the light brown sugar developed a rich butterscotch flavor. To add both texture and flavor to the cookies, we included chocolate chips and pecans. We also tried butterscotch chips, but we found that they did little for this recipe. On a whim, we included white chocolate chips with the semisweet chips, and we were surprised that they produced the best blondie yet.