Beat zucchini, sugar, eggs, oil, and lemon extract. Sift together dry ingredients and stir in with lemon zest. Fold in the blueberries gently. Pour into a well greased and floured Bundt cake pan.
Bake at 325 for about 65 minutes or till toothpick comes out clean. Let sit in pan for 5-10 minutes, then invert onto cooling rack. Cool completely and frost with lemon cream cheese frosting.
To make the frosting - Beat butter and cream cheese till smooth. Add powdered sugar, salt, zest, and enough lemon juice to make a spreadable consistency.