Adjust oven rack to the middle position and preheat to 325°F. Grease a 9” x 5” loaf pan and set aside.
In a large mixing bowl, whisk to combine the oil and sugar. Add the eggs and whisk well. Add the milk, rose water, baking soda, advieh, and salt, and whisk to combine. Stir in the zucchini and pistachios, if using, with a large spoon, then fold in the flour until combined.
Pour the batter into the greased loaf pan and sprinkle lightly with additional brown sugar and advieh.
Bake for 55 to 60 minutes, or until the internal temperature registers 195°F (you can also test with a toothpick). Let the bread cool in the loaf pan for 10 minutes, then transfer it to a wire rack to cool for 20 minutes before slicing it with a sharp, serrated knife.
Store it in the refrigerator for 5 to 7 days or in the freezer for up to 3 months or so.
Oil: I used extra-virgin olive oil in one version and vegetable oil in the second. I think the olive oil made it a bit more savory, which was nice, but either one works. You could also use coconut oil (unrefined won't lend much flavor to the final product).
Sweetener: I used honey in the first version but found the flavor too bold (this largely depends on the intensity of your honey). I switched to brown sugar in the second version but you could use maple syrup, granulated sugar, or agave nectar. I also tried to reduce the sugar to 1/3 cup in one version but the flavor was flat. The little bit of extra sugar is well worth it.
Rose water: the amount called for in the recipe just gives a hint of floral aroma. You could always bump it up to 1 tsp if you want a bit more to come through.
Squash amount: the original recipe calls for 1-1/2 cups of squash but I packed even more in with 2 cups. I think that is approaching the max amount the bread can hold but maybe you can get in even more (it's like the kitchen version of double dare).
Flour: you could try whole wheat, spelt, rye or any number of your favorite flours in this recipe. Also try combining 1/2 all-purpose with 1/2 of another. Each will lend a slightly different flavor.