Preheat oven to 350 degrees F. Grease 12 muffin cups or line with paper liners.
Whisk together flours, sugars, baking soda, cinnamon, and salt together in a bowl.
Whisk olive oil, sour cream, egg, and vanilla extract in a separate bowl until smooth.
Stir wet ingredients into flour mixture until batter is just moistened. Batter will be very thick. Stir in shredded zucchini and mix well. Gently fold in blueberries.
To make the streusel, combine flour, sugar, butter, cinnamon, and pecan pieces. Use a fork or a pastry blender to evenly distribute butter chunks.
Fill prepared muffin cups 2/3 full with batter. A cookie scoop works great for this task. Top with equal amounts of streusel.
Bake in preheated oven until a toothpick inserted into the center of a muffin comes out clean, 20 to 25 minutes for regular sized muffins or 25-30 minutes for jumbo ovens (cooking times will vary).