These butterscotchy blondies get their big flavor from a little bourbon, vanilla, dark coconut sugar, toasty hazelnuts, browned butter and salted tops. I love the whole wheat flour here and like to hand chop the chocolate so there are larger pockets and shards throughout versus neat and tidy chips. That said, chocolate chips work just fine — and you could substitute in any nut you’d like if hazelnuts aren’t your jam. These are quite rich and decadent, so I suggest slicing them in smaller squares; they keep great at room temperature for a good 5 days or freeze them for future late night snacking.
Preheat the oven to 350 F°. Nestle a sheet of parchment paper into an 8×8″ pan (this will help you lift the blondies out very easily) or, alternatively, grease the pan, dust with flour and set aside.
Lay hazelnuts on a small rimmed baking sheet and toast until fragrant, about 4 minutes (if you’re using whole hazelnuts and plan to just chop them, these take longer to toast, about 8 minutes).
In a small light-colored saucepan (this helps so you can see the color change that will occur), melt the butter over medium heat, stirring occasionally. Cook until the butter begins to foam, about 5 minutes. Continue cooking until the foam subsides and little brown bits appear at the bottom of the pan, smelling fragrant and nutty. During this time, stir vigorously with a wooden spoon, scraping the bits from the bottom of the pan. Pour butter into a heatproof bowl, and stir for 2-3 minutes to allow it to cool to room temperature.
Once butter is cool (but still liquid), whisk in the sugar, eggs,vanilla and bourbon.
In a separate mixing bowl, whisk together both flours, baking powder, and salt. Using a rubber spatula, fold the dry ingredients into the wet ingredients and stir until combined. Fold in the chocolate and toasted hazelnuts.
Scrape batter into prepared pan and smooth the top with the rubber spatula. Sprinkle with flaky salt.
Bake blondies for 30-35 minutes or until tops are light golden brown and firm (can’t really do the toothpick test as there’s lots of chocolate going on). Let cool completely before lifting out of pan to slice.
Top with additional sprinkle of flaky salt, and cut into 16 small squares (or 9 large squares) and serve.
Note on brown sugar / coconut sugar: I love the dark flavor of coconut sugar in these, but if brown sugar is more readily available to you, just swap it in but do it by weight (as brown sugar is heavier than coconut sugar). So while 1 3/4 cups of coconut sugar weighs 300g, you can use just 1 1/2 cups of brown sugar as it has an equal weight.