In a small bowl, whisk together 2 teaspoons of egg replacer powder with 4 tablespoons of water. Whisk until frothy and well combined. Set aside.
Preheat oven 180°C, fan forced. Grease and line a 8x8 inch square pan with baking paper.
In a medium size bowl, whisk together the dry ingredients, flour, baking powder and salt. Set aside.
In a large bowl, mix the melted butter, sugar, lemon zest, lemon juice and egg replacer mixture prepared in step 1. Then add vanilla extract and stir until smooth.
Gradually stir the dry ingredient mix into the wet ingredients until just combined. Gently fold in the fresh blueberries.
Pour the batter into the prepared pan and smooth over the surface. Bake for 30-35 minutes or until a toothpick inserted into the middle comes out clean.
Allow the blondies to cool completely in the pan. Once fully cooled, remove and cut into squares.