Preheat oven to 350 degrees F. Grease a 9-inch spring-form pan.
Sift together the flour, salt, baking powder, cinnamon, and sugar and set to the side. In another bowl mix together the egg, sour cream, and melted butter. Pour the egg mixture into the bowl with the dry ingredients and blend just until incorporated. Add the zucchini and blueberries and gently fold in.
Spread in the prepared spring form pan.
Prepare the topping. Mix all the dry ingredients together and add the melted butter. Mixed until all ingredients are combined. Sprinkle over top of the cake.
Bake in the preheat 350 degree F oven for 55 to 60 minutes or until a wooden pick comes out clean.