Brown Butter Butterscotch Blondies

Name: Brown Butter Butterscotch Blondies
Prep time: 22 min
Cook time: 40 min
Total time: 1 h 2 min
Yield: 24 servings
Cuisine: American
Ingredients: 1 cup (2 sticks) (227 g) unsalted butter, cut into tablespoon-size pieces; 1¾ cups, firmly packed (350 g) light or dark brown sugar, breaking up any lumps; ¾ tsp (4½ g) fine sea salt; 2 whole (100 g) large eggs, at room temperature; 1 whole (18 g) large egg yolk, at room temperature; 1 tbsp (15 ml) pure vanilla extract; 2 cups (250 g) all-purpose flour, spooned into the cup and leveled; 1 tsp (4 g) baking powder; 1 cup (170 g) butterscotch chips, for folding into the batter; ½ cup (85 g) butterscotch chips, for sprinkling on top; ½ tsp (1½ g) flaky sea salt, for finishing

From the MyKitchenBank Kitchen

Chewy, crinkly-topped blondies built on nutty brown butter and dark brown sugar, studded with melty butterscotch chips and finished with flaky salt.

Prep: 22 min
Cook: 40 min
Wait: 1 hr 40 min
Total: 2 hr 42 min
Makes: 24 bars (one 9×13-inch pan)

Jump to recipe ♡ Save

Ingredients

24 servings

1 cup (2 sticks) (227 g) unsalted butter, cut into tablespoon-size pieces
1¾ cups, firmly packed (350 g) light or dark brown sugar, breaking up any lumps
¾ tsp (4.5 g) fine sea salt
2 whole (100 g) large eggs, at room temperature
1 whole (18 g) large egg yolk, at room temperature
1 tbsp (15 ml) pure vanilla extract
2 cups (250 g) all-purpose flour, spooned into the cup and leveled
1 tsp (4 g) baking powder
1 cup (170 g) butterscotch chips, for folding into the batter
½ cup (85 g) butterscotch chips, for sprinkling on top
½ tsp (1.5 g) flaky sea salt, for finishing

Equipment (8)

9×13-inch (23×33 cm) light-colored metal baking pan
Parchment paper
Light-colored medium saucepan (3-quart / 3 L) so you can see the butter color change
Large mixing bowl
Whisk and rubber spatula
Measuring cups and spoons or a kitchen scale
Wire rack
Sharp knife

Steps

Before you start

Eggs should be at room temperature (set them out 30 minutes ahead, or sit them in warm tap water for 5 minutes) so the batter mixes smoothly.
Read the whole recipe first: the brown butter needs about 10 minutes to cook and another 10 to cool before you add eggs.
Use a light-colored metal pan if you can; dark pans bake the edges faster and can dry out the bars.
Don't skip the full cooling time. Warm blondies are gooey and won't slice cleanly.

1
Preheat and line panOven 350°F / 175°C
- Position a rack in the center of the oven and heat to 350°F (175°C).
- Line a 9×13-inch (23×33 cm) pan with parchment, leaving 2 inches of overhang on the two long sides to use as handles.
+ Show details− Hide details
Ready when: Oven is fully preheated and the pan is lined with parchment pressed into the corners.
Tip: Lightly grease the pan before pressing the parchment in so it stays put.
2
Brown the butter
- Melt the butter in a light-colored 3-quart saucepan over medium heat, stirring occasionally.
- It will foam, then crackle.
- Once the crackling quiets, stir constantly and scrape the bottom for 1 to 2 minutes more.
- Total time is about 8 to 10 minutes.
+ Show details− Hide details
Ready when: The foam subsides, the butter smells nutty, and the milk solids on the bottom are deep golden-brown (like toasted hazelnut), not black.
Tip: Browned butter turns from perfect to burnt in seconds. Pull the pan off the heat the moment it smells nutty and the specks are amber-brown.
3
Cool butter on sugar
- Immediately pour all the butter, including every brown speck, over the brown sugar and salt in a large mixing bowl.
- Stir with a spatula to combine.
- Let the mixture sit for 10 minutes so it is warm, not hot.
+ Show details− Hide details
Ready when: The bowl feels warm, not hot, to the touch.
Tip: Pouring into a bowl stops the butter from continuing to cook in the hot pan.
4
Whisk in eggs
- Add the eggs, egg yolk and vanilla to the butter-sugar mixture.
- Whisk vigorously for about 1 minute.
+ Show details− Hide details
Ready when: The mixture is thick, glossy, and looks like caramel sauce, with no streaks of egg.
Tip: Whisking well here helps create the shiny, crinkly top.
5
Fold in flour
- Sprinkle the flour and baking powder over the batter.
- Switch to a rubber spatula and fold gently until just combined and no dry streaks remain, about 20 strokes.
+ Show details− Hide details
Ready when: The batter is thick and sticky with no visible flour.
Tip: Overmixing makes blondies tough and cakey.
6
Add butterscotch chips
- Fold the 1 cup (170 g) of butterscotch chips into the batter until evenly distributed.
+ Show details− Hide details
Ready when: Chips are evenly spread through the batter.
7
Fill pan and top
- Scrape the batter into the prepared pan.
- With damp fingers or an offset spatula, press it into an even layer, including the corners.
- Scatter the remaining ½ cup (85 g) chips over the top, then sprinkle with the flaky salt.
+ Show details− Hide details
Ready when: The batter is level and uniformly about ¾ inch (2 cm) thick.
Tip: Dampening your hands keeps the sticky batter from pulling up as you spread it.
8
Bake the blondiesOven 350°F / 175°C
- Bake at 350°F (175°C) for 28 to 32 minutes, rotating the pan front to back after 15 minutes.
+ Show details− Hide details
Ready when: Edges are set and golden-brown, the top is crinkly and no longer shiny-wet, and a toothpick in the center comes out with a few moist crumbs (center about 200°F / 93°C). The center will still look slightly soft.
Tip: Pull them when the center is slightly underdone. They keep cooking in the hot pan and overbaked blondies turn dry.
9
Cool completely
- Set the pan on a wire rack and cool for 90 minutes at room temperature, until fully cool.
+ Show details− Hide details
Ready when: The pan is no longer warm to the touch and the center feels firm.
Tip: For very neat squares, chill the cooled pan in the fridge for 30 minutes before cutting.
10
Slice and serve
- Lift the slab out using the parchment handles and place it on a cutting board.
- Cut into 4 rows by 6 rows to make 24 bars, wiping the knife clean between cuts.
+ Show details− Hide details
Ready when: Bars have clean edges and hold their shape.
Tip: Use a large sharp knife and press straight down rather than sawing.

Good to know

Tips

Use a light-colored pan to judge the butter color, and keep stirring near the end; the solids burn fast.
Scrape every brown speck into the batter. Those toasted milk solids provide the nutty flavor.
Measure flour by spooning it into the cup and leveling, or weigh it. Packing the cup makes dry, cakey bars.
Underbake slightly for a fudgy, chewy center; the bars firm up as they cool.

Make ahead

"Brown the butter up to 3 days ahead and refrigerate it in an airtight container; re-melt gently until just liquid and let it cool to warm before using. The baked slab can be made a day ahead, kept covered in the pan, and cut the next day."

Storage & reheating

Room temperature in an airtight container, layered with parchment, for up to 4 days. Refrigerate for up to 1 week (bring to room temperature before serving). Freeze, wrapped individually and then in a freezer bag, for up to 3 months; thaw at room temperature for 1 hour, or warm a bar in a 300°F (150°C) oven for 5 minutes.

Substitutions

butterscotch chips → white chocolate chips, toffee bits, or semisweet chocolate chunks. Use the same amount. Toffee bits add crunch; white chocolate makes the bars sweeter.
unsalted butter → salted butter. Reduce the fine sea salt to ¼ teaspoon (1.5 g).
all-purpose flour → 1:1 gluten-free baking flour blend. Let the batter rest 10 minutes before baking; the texture will be slightly more tender.
flaky sea salt → ¼ teaspoon coarse kosher salt. Sprinkle lightly so it doesn't taste too salty.