Preheat the oven to 350°F and generously butter 2 loaf pans (9 x 5 x 3-inches).
Wrap the grated zucchini in a double thickness of cheesecloth and wring out the excess liquid (see notes below). Place in a small bowl and set aside.
In a separate bowl, whisk the eggs, buttermilk, olive oil and pesto together until well blended. Set aside.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, salt, sugar, pine nuts and Parmesan cheese. Add the wet ingredients, zucchini and scallions and mix until well blended.
Note: The mixture will be stiff - more like a dough than a batter.
Divide between the prepared loaf pans and bake until a toothpick inserted into the center comes out clean, 40 to 50 minutes.
Cool in the pans for 5 minutes, then turn onto cooling racks.
Tips for Making This Recipe
About the zucchini:
A half-pound (8 ounces) of zucchini should yield about 1-1/2 cups grated. For best results, use the largest holes on a box grater. Once you squeeze out the majority of the excess liquid, you should be left with about 1 cup.