Preheat oven to 350 degrees. Line a 13x9-inch pan with foil and apply nonstick spray.
In a large bowl, cream together the butter and white sugar. Add eggs one at a time followed by the lemon zest, lemon juice, and lemon extract. Stir in the flour and salt. When those are just incorporated, add the white chocolate chips and macadamia nuts.
Pour the batter into the ready pan. Bake for 25-35 minutes, until it passes the toothpick test in the middle.
Immediately after that is done baking, make the glaze by stirring together the confectioners' sugar and reserved lemon juice and zest. Use a chopstick or similar tool to poke small holes across the top of the blondies. Pour the glaze over the top and use a spoon to distribute it evenly. Sprinkle the remaining nuts on top.
Let pan cool completely. Use the foil to lift the contents onto a cutting board. Slice into bars. Store in a sealed container with wax paper or parchment between the layers.
OM NOM NOM!