Ingredients

• 1 cup (226 g) unsalted butter, melted

• 1¼ cups (250 g) firmly‑packed brown sugar

• ½ cup (100 g) granulated sugar

• 2 large eggs + 1 egg yolk, room temperature

• 2 teaspoons vanilla extract

• 2¼ cups (285 g) all‑purpose flour

• 2 teaspoons cornstarch

• ½ teaspoon baking powder

• 1 teaspoon salt

• ⅔ cup (115 g) white chocolate chips (or substitute your choice of add‑ins)

• 1 cup (130 g) chopped walnuts (optional)
  
  

Instructions

1. Preheat your oven to 350 °F (175 °C) and line a 13×9‑inch baking pan with parchment paper (or lightly grease and flour).

2. In a large bowl, stir together melted butter, brown sugar and granulated sugar until combined.

3. Add the eggs + yolk and vanilla extract; mix until smooth.

4. In a separate bowl, whisk together flour, cornstarch, baking powder and salt.

5. Gradually fold the dry ingredients into the wet mixture until just combined (avoid over‑mixing).

6. Fold in the white chocolate chips and chopped walnuts (if using).

7. Spread the batter evenly into the prepared pan and smooth the top with a spatula.

8. Bake for 25‑30 minutes, or until the edges are lightly golden and a toothpick inserted near the center comes out clean or with a few moist crumbs.

9. Remove from oven and allow the bars to cool completely in the pan (about 30 minutes) before lifting out via the parchment and cutting into squares.
   
   

Chefify Tips

• Melted butter contributes to a rich, chewy texture — don’t substitute with softened butter.

• Use a firm packing of brown sugar for that deep caramel‑vanilla flavour.

• Avoid over‑baking; blondie bars should be slightly fudgy in the center and will set as they cool.

• You can swap white chocolate chips and walnuts with other add‑ins like dark chocolate, pecans, caramel bits or dried fruit.

• Press a light layer of flaky sea salt on top immediately after baking for a gourmet touch.

• Store fully cooled bars in an airtight container at room temperature for up to 4 days; they also freeze well for future indulgence.