Special equipment: mortar and pestle
Preheat the oven to 250 degrees F and place a baking sheet inside.
Grate the zucchini on the large holes of a box grater, grating around the core and seeds, and discarding them. You should have about 2 cups grated zucchini.
In a large bowl, whisk together the eggs, buttermilk, oil, muscovado sugar, granulated sugar, vanilla and orange zest until smooth. Stir in the zucchini.
In a small bowl, whisk together the all-purpose flour, whole wheat flour, cinnamon, baking powder and salt until combined. Whisk the dry ingredients into the wet ingredients and mix until just combined. Do not over mix. Rest the batter for 20 minutes.
While the batter rests, make the apricot butter. Put the butter, apricot preserves and a pinch salt into a mortar and pestle and work together until well blended. Set aside.
Heat a large cast-iron skillet over medium heat. Brush generously with clarified butter. Using a scant 1/4-cup of the batter for each pancake, pour the batter into the pan and cook until bubbles appear on the surface, 2 to 3 minutes. Flip the pancakes and cook until golden brown on the bottom, another 1 to 2 minutes. Transfer the pancakes to the prepared pan in the oven to keep warm as well as ensure that they're all cooked through when they're served. Repeat with the remaining batter.
Serve 3 pancakes per person, spread with apricot butter and top with warm maple syrup, walnuts and a dusting of confectioners' sugar if using.