Preheat oven to 375 degrees F. Line a 9-inch loaf pan with parchment paper so it hangs off the sides. Grease with cooking spray and set aside.

In a large mixing bowl, whisk together the flour, sugar, baking soda, baking powder, salt, and cinnamon. In a separate bowl, whisk together the yogurt, eggs, oil, and vanilla. Make a well in the center of the dry ingredients and pour in the wet, along with the shredded zucchini. Stir with a rubber spatula until the mixture comes together and no dry streaks remain. Be careful not to over mix the batter at this point.

To make the streusel topping, in a bowl combine the flour, brown sugar, salt and cinnamon. Add the butter and work it in with a pastry blender or your hands until coarse crumbs form the size of peas. Stir in the oats and chocolate chips.

Pour half of the batter into the prepared loaf pan, smoothing out into an even layer. Sprinkle with half of the streusel, and then pour in the remaining batter, smoothing out once more. Top with the remaining streusel.

Bake until golden brown and a toothpick inserted in the middle, comes out clean, about 45 minutes to 1 hour. Remove from the oven and allow to cool for 15 minutes in the pan. Using the excess overhang of parchment paper, carefully lift the loaf from the pan and place on a wire rack to cool completely. Cut into slices and serve! Leftovers can be wrapped in plastic wrap and stored at room temperature for up to 3 days. Enjoy!