Ingredients
Scale
- 3/4 cup (170 g) unsalted butter
- 1 cup (220 g) packed dark brown sugar
- 1/4 cup (50 g) granulated sugar
- 1/2 cup (120 ml) pure maple syrup
- 2 large eggs, at room temperature
- 1 large egg yolk, at room temperature
- 2 teaspoons pure vanilla extract
- 1 3/4 cups (220 g) all purpose flour, spooned and leveled
- 1 teaspoon baking powder
- 1/2 teaspoon fine sea salt
- 1 teaspoon ground cinnamon
- 1 1/2 cups (170 g) walnut halves, toasted and coarsely chopped, divided
- Flaky sea salt, for finishing
Instructions
- Preheat the oven to 350°F (175°C). Line an 8×8 inch baking pan with parchment paper, leaving overhang on two sides for easy lifting.
- Spread the walnuts on a baking sheet and toast for 8 to 10 minutes, until fragrant and lightly golden. Let cool, then chop coarsely and set aside 1/3 cup for the topping.
- Melt the butter in a light colored saucepan over medium heat. Swirl often and cook 5 to 7 minutes, until it turns amber and smells nutty with brown flecks at the bottom.
- Pour the brown butter into a large mixing bowl and let cool for 10 minutes. Whisk in the brown sugar, granulated sugar, and maple syrup until smooth and glossy.
- Whisk in the eggs, egg yolk, and vanilla extract one at a time, beating well after each addition until the mixture looks thick and shiny.
- In a separate bowl, whisk the flour, baking powder, fine sea salt, and cinnamon. Fold the dry mixture into the wet mixture just until no flour streaks remain.
- Fold in 1 cup of the chopped toasted walnuts, reserving the rest for the top.
- Spread the thick batter evenly into the prepared pan with a spatula. Sprinkle the reserved walnuts over the surface and press them in lightly.
- Bake for 28 to 32 minutes, until the edges are set and golden and the center looks just barely set with a slight jiggle.
- Cool completely in the pan on a wire rack for at least 2 hours. Lift out using the parchment sling, sprinkle with flaky sea salt, and cut into 16 squares.
- Prep Time: 15
- Cook Time: 30