Preheat the oven to 350°F. Line an 8x8 inch light colored aluminized steel baking pan with parchment paper. Set aside.
Place the butter and white chocolate in a microwave safe bowl.
1/2 cup butter, unsalted, 1, 4 oz. white chocolate bar
Microwave for 1 minute (cover with a paper towel to prevent splatter), then stir. Continue heating in ~15-30-second increments, stirring between, until the mixture is melted and smooth but not scorched. Remove from the microwave allow to cool slightly.
Add the sugar and lemon zest in a large mixing bowl. Rub the sugar and lemon zest between your fingertips to create a lemon sugar. This helps release the natural oils and infuses more lemon flavor into the brownies.
3/4 heaping cup granulated sugar, 2 Tbsp. lemon zest (I used 2 large lemons)
Add the eggs and extracts and whisk for about 1 minute.
2 large eggs, room temperature, 1 large egg yolk, room temperature, 1 tsp. lemon extract, 1 tsp. vanilla extract
Pour in the white chocolate/butter mixture and fold until combined.
Add in the flour, salt, and baking powder. Fold a few times.
1 cup + 2 Tbsp. all purpose flour, spooned and leveled, 1/2 tsp. salt, 1/8 tsp. baking powder
Add the lemon juice last.
2 Tbsp. lemon juice (fresh)
Fold until incorporated, do not over mix. (You can fold in some white chocolate chips in this step too, if desired).
Pour into prepared pan.
Bake for ~25-30 minutes. The edges will look golden brown, (the tops won't be browned), and a toothpick inserted in the center should come out mostly clean, a few moist crumbs are OK. As always, be careful not to over bake. Allow to cool completely.
Whisk/stir together the powdered sugar and lemon juice in a small bowl. It should be thick, but pourable. Spread over the cooled lemon brownies with an offset spatula.
1 cup powdered sugar, 2 Tbsp. lemon juice (fresh)
Garnish with lemon zest on top (optional) and allow to set up for ~15-30 minutes before slicing and enjoying...if you can wait! 🤣 Store at room temperature for 2-3 days, or I really enjoy these brownies cold, too!