# What You'll Need:
→ Blondie Base
01 - 1/2 cup unsalted butter, melted and slightly cooled
02 - 3/4 cup packed light brown sugar
03 - 1/4 cup granulated sugar
04 - 1 large egg
05 - 1 1/2 teaspoons pure vanilla extract
06 - Zest of 1 lemon
07 - 2 tablespoons fresh lemon juice
08 - 1 1/2 cups all-purpose flour
09 - 1/2 teaspoon baking powder
10 - 1/4 teaspoon fine sea salt
→ Mix-ins
11 - 1/2 cup white chocolate chips or chopped white chocolate
12 - 3/4 cup fresh blueberries, plus a few extra for topping
# How to Make It:
01 - Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper leaving an overhang to lift the bars out after baking.
02 - In a large bowl, whisk the melted butter with the light brown sugar and granulated sugar until fully combined and smooth.
03 - Whisk the egg into the butter-sugar mixture, then add the vanilla, lemon zest and lemon juice until evenly distributed.
04 - In a separate bowl, whisk together the all-purpose flour, baking powder and sea salt to aerate and combine.
05 - Add the dry mixture to the wet ingredients and stir gently just until no dry streaks remain; avoid overmixing to keep the crumb tender.
06 - Carefully fold in the white chocolate and blueberries, reserving a few to scatter on top for appearance.
07 - Spread the batter evenly in the prepared pan, top with reserved berries and chips if using, and bake 28–32 minutes, until the center is set and edges are lightly golden.
08 - Cool completely in the pan on a wire rack, then lift out using the parchment overhang and cut into 12 bars.