For the Blondies:

1. Preheat the Oven: Preheat to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper or grease it lightly.

2. Melt the Butter and White Chocolate: In a saucepan, melt butter and white chocolate over low heat, stirring frequently. Remove from heat and let cool slightly.

3. Mix the Wet Ingredients: In a large bowl, whisk together granulated sugar and lemon zest. Add melted butter and white chocolate, then beat in eggs, egg yolk, lemon extract, and vanilla extract. Mix until smooth.

4. Add the Dry Ingredients: In another bowl, whisk together flour, salt, and baking powder. Gradually add dry ingredients to the wet mixture, stirring until just combined. Mix in fresh lemon juice.

5. Bake the Blondies: Pour batter into the prepared pan and smooth out the top. Bake for 25-30 minutes, until edges are golden and a toothpick inserted into the center comes out clean or with a few moist crumbs.

6. Cool: Let the blondies cool in the pan for 10 minutes before transferring them to a wire rack to cool completely.

For the Glaze:

7. Make the Glaze: In a small bowl, whisk together powdered sugar and lemon juice until smooth and pourable. Adjust consistency as needed with more lemon juice (if too thick) or powdered sugar (if too thin).

8. Glaze the Blondies: Once cooled, drizzle the glaze over the blondies in a zigzag pattern. Let set for 10-15 minutes before slicing.