Brown Butter Blondies with Butterscotch Toffee

The Fearless Baker received a ton of positive press leading up to its release (and after), and Erin McDowell is the mind behind many of the "Genius" dessert recipes on Food52, so I had pretty high expectations for her first cookbook. These butterscotch blondies grabbed my attention immediately when I flipped through. They looked simple enough to make any time, while the butterscotch sauce component offered something more interesting than a basic blondie recipe.

My first attempt at these didn't go as smoothly as I expected from all the hype surrounding this cookbook. First, my butterscotch sauce was unappealingly grainy in texture, as the brown sugar isn't given enough time to fully dissolve into the caramel sauce. I tried rescuing it by reheating the cooled sauce and letting it come to a boil for 3-5 minutes before pulling it off the heat. [This trick worked, but since then I haven't been able to repeat the "reboil" to fix this butterscotch sauce, so I can't recommend it as the solution.]

Once I had my butterscotch sauce cooling, I set about making the blondies. My batter didn't look nearly as light in color as the batter in Erin's book, which confused me, but I'd followed her rather vague ("mix until well-incorporated") directions, and these were "just blondies", so how hard could they be? I soldiered on.

Caleb insisted on having chocolate chips in these, because he doesn't see the point in blondies without any chocolate. So, in went some semi-sweet Guittard chocolate chips. After I got the batter into the specified 9x9-inch pan, I drizzled the top with butterscotch sauce. My sauce did not stay put like Erin's seemed to, so I didn't really bother swirling it through the batter.

Thirty-three minutes later, my blondies did not look anywhere close to done in the middle (although all the butterscotch sauce on top made it hard to tell). After about 40 minutes, the blondies were approaching too done on top, so I crossed my fingers and took them out.

When we cut into them after an hour rest, I was dismayed by the incredibly oily, underdone insides. They firmed up a little overnight and were certainly edible, but I wasn't enamored with the recipe. I wanted to see if I could "fix" it and produce non-oily, flavorful, repeatable butterscotch blondies.

In my quest, I stumbled across a post by Stella Parks on why your blondies are always underdone in the middle and resolved to try Erin's recipe again with Stella's advice about how the batter should look after beating in the eggs (as light in color as Erin's picture of her batter in the cookbook, achieved only after at least 5 minutes of beating with my Pro standmixer).

Sadly, I failed again with the butterscotch sauce. I tried cooking it longer, monitoring the temperature it reached and how long it stayed there, but my butterscotch was still grainy after cooling. In frustration, I reheated it once more and brought the temperature up even higher. As luck would have it, my butterscotch sauce was still grainy, but now it was also a lot harder in texture... more like a toffee than a sauce. After it had cooled enough to handle, I poured the thick sauce into a shallow glass dish and cut it into squares, let it cool, then threw it into the fridge while I decided what to do next.

I made the brown butter blondie batter following Stella's advice and was happy to see it transform into the pale tan batter that is (apparently) the hallmark of a properly-beaten blondie batter. Thinking I might have better luck with a thinner batter, I poured the batter into a 9x13-inch pan, then dotted the surface with chunks of the "failure" butterscotch toffee. I baked these blondies for 30 minutes, let them cool completely, then took them to work. Since they were baked in a bigger pan, this version was thinner and a bit more delicate (read: hard to remove from the baking pan in one piece!), but everyone loved them. The problem was, I couldn't exactly say what I did to produce the brown butter butterscotch toffee that was the key feature of these.

Two more attempts at making the brown butter butterscotch toffee/sauce reproducible, and I decided to give up for a while and bake other things. Meanwhile, I did some candy temperature research, looked back at my notes on the "successful-failure", and tried again. Finally, I achieved brown butter butterscotch toffee perfection. The trick was when you add the cream to the butter and brown sugar, as well as getting your brown butter brown sugar sauce to just past 245 F, but catching it before it reaches 250 F.

The next feature I wanted to optimize was the thinness of these blondies. In previous struggles with blondies, I'd "learned" to bake blondies in a 9x13" pan rather than the 9x9" pan usually specified in the recipe. This helped the blondies bake through instead of remaining a forever underdone, sad, gooey disaster of a bake. But maybe that solution was no longer necessary? Maybe these blondies, as delicious as they were baked in a 9x13" pan, would actually taste better baked in a 9x9" pan, where the dough properly filled out all the corners and created a nice, thick bar cookie?

Obviously, I had to test this, so I baked one pan of each, plus a pan of butterscotch blondies from Home Baked Comfort (which had also given me trouble in the past), then took the three pans of blondies into work for a vote. The almost-unanimous vote was for these butterscotch blondies baked in a 9x9" pan. I disagree with the consensus- I prefer these thinner because I find them not quite as densely sweet - but both options are good. The 9x13" pan of these came in "second" place, with the blondies from Home Baked Comfort a very distant third.

Several people, including Caleb, feel that blondies should always contain chocolate because "everything is better with chocolate". Feel free to add some sprinkled chopped chocolate or bittersweet chocolate chips over the top; I would advise you against mixing them into the batter as it makes the blondies (in my opinion) a little too oily and the chocolate obscures the taste of the browned butter. Still, the non-blondie purists will appreciate them.

These keep quite well for several days in an airtight container, or they can be stored in the freezer for up to 2 months.

Heavily adapted from the Fearless Baker

Butterscotch Blondies with Brown-Butter Butterscotch Toffee

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Course: Dessert

Cuisine: American

Keyword: browned butter, butterscotch, the fearless baker, toffee

Prep Time: 50 minutes minutes

Cook Time: 50 minutes minutes

Cooling time: 3 hours hours

Total Time: 4 hours hours 40 minutes minutes

Servings: 16 people

Ingredients

Brown-Butter Butterscotch Toffee (makes enough for 2-3 batches of blondies)

• 6 tablespoons (85 grams; 3 oz) unsalted butter
• 1 ¼ cups (270 grams) packed dark brown sugar
• ½ cup (105 grams) heavy cream
• 1 teaspoon (5 grams) vanilla extract
• ½ - 1 teaspoon (2-4 grams) flaky sea salt (depending on your preference)

Butterscotch Blondies

• 12 tablespoons (170 grams; 6 ounces) unsalted butter
• 1 cup (212 grams) light brown sugar packed
• ½ cup (99 grams) granulated sugar
• 2 large eggs at room temperature
• 1 tablespoon (15 grams) pure vanilla extract
• 1 ¼ cups (151 grams) all-purpose flour
• ¾ teaspoon (4.5 grams) baking powder
• ¼ teaspoon (1 gram) kosher salt
• optional: 1 cup bittersweet chocolate chips or nuts of choice
• ⅓-1/2 batch (~100 grams) brown-butter butterscotch sauce, toffee, or other caramel sauce

Instructions

Brown-Butter Butterscotch Toffee

• Slice the butter into 15-20 pieces, place in a heavy-bottomed saucepan over medium heat and stir constantly until melted. As it melts, the butter will foam. Keep cooking the butter after the foam subsides for another 7-10 minutes, continuing to stir occasionally. It is done once the milk solids turn golden brown and the butter takes on a nutty fragrance.
• Stir together the brown sugar and heavy cream until no more big clumps of brown sugar remain. The sugar should be basically fully suspended in the cream. Add the brown sugar-cream to the browned butter and bring the sauce to a slow simmer over medium heat, stirring it occasionally. This should not take very long at all. It may look like some of the butter breaks out of the suspension, just keep stirring to reincorporate it.
  
• Keeping the heat at medium (6/10 on my stovetop), stop stirring and allow the sauce to bubble and thicken for about 5 minutes, until it reaches 245-247 F. [If you are aiming for a butterscotch sauce rather than a toffee, stop cooking after about 4 minutes of constant simmering.]
  
• Remove from the heat and stir in the vanilla and salt. Transfer the toffee to a heat-proof shallow dish and let it cool for 5-10 minutes. Once it has cooled to lukewarm, use a butter knife to score the semi-solid butterscotch into chunks. At this point, the room-temperature toffee can be used immediately for the blondies, or, the formed toffee pieces can be allowed to cool completely and then stored in the refrigerator for several weeks.

Butterscotch Blondies

• Preheat the oven to 350°F. Cover the bottom and sides of a 9x9-inch baking pan (square or circular) or 9x13-inch baking pan with parchment paper.
• If using nuts, place on a baking sheet in a single layer and toast until golden in the oven.
• In the bowl of a stand mixer fitted with the paddle attachment, add the butter, brown sugar, and sugar, then beat at medium-low speed until fluffy and lightened in color, about 4-5 minutes. Stop every minute or so to scrape down the sides and bottom.
• Add the eggs one at a time, beating well (about 60 seconds at least) on medium speed after each addition. After both eggs have been added, continue beating at medium speed another 2-5 minutes, until the batter has gained visible volume and is very pale in color. Add in the vanilla* and beat briefly to incorporate.
  
• In a separate bowl, whisk together the flour, baking powder, and salt. Add the dry ingredients to the stand mixer bowl and beat in at low speed until they are just incorporated. Be careful not to overmix.
  
• Spoon the dough in to prepared pan and smooth the top. It will look like too little dough for the pan, but continue gently spreading it out, it should be a very thin layer (and if you can't quite reach the edges, that's okay). If using chocolate or nuts, sprinkle these across the top of the dough.
• Scatter the small pieces of butterscotch toffee across the surface of the dough. [Alternatively, if you are using a butterscotch sauce, drizzle the sauce across the top, then use the tip of a knife to gently swirl the sauce into the dough.]
  
• Bake for 35 minutes (9x9 pan) or 30 minutes (9x13 pan), until shiny golden brown, slightly cracked on top, and just set in the center. Allow to cool in pan for at least 20-30 minutes, then gently and carefully transfer to a metal cooling rack by placing the cooling rack, covered with another piece of parchment paper, on top of the pan and flipping the pan upside down to drop the blondies onto the rack. [There is no other way to remove the blondies without cracking them unless you leave them to cool completely in the pan - even then, they might crack.]
  
• These are best eaten after a 12 hour rest, and will keep 4-5 days stored in an air-tight container at room temperature.

Notes

While I think these are far better without add-ins, your opinion may differ! Optional add-ins (or replacements for the butterscotch sauce): ⅔ - 1 cup dark or bittersweet chocolate chunks (150 grams) or chopped toasted nuts (100 grams).