Place shredded zucchini in a clean kitchen towel and wring out any extra moisture; set aside.
In the bowl of a stand mixer, blend eggs, applesauce, oil, sugar, and vanilla.
Add in zucchini and mix well.
Gradually add flour to mixer bowl, one cup at a time, while mixer is set to low speed.
Add in salt, baking powder, baking soda, and cinnamon and mix once more.
Remove bowl from mixer and gently fold in blueberries.
Spread batter even among two greased loaf pans.
In a smaller bowl, blend streusel topping ingredients with a pastry blender or two knives.
Sprinkle streusel evenly over pans.
Bake at 350 degrees for 50 minutes - 1 hour or until a cake tester comes out clean. (Cover breads with foil for the last 15 minutes if top is getting over browned.)