Try to drain most of the water from the zucchini. I’ll usually let mine sit in a strainer for a few minutes and then soak up some moisture with a couple paper towels.
If you don’t have buttermilk on hand (do people normally?) replace it with ¼ cup milk (dairy, almond, soy, whatever) mixed with 1 ½ teaspoon lemon juice. Stir it up and let it sit for a minute or two before using.
Adding ¼ cup chopped walnuts on top with the chocolate chips and brown sugar would be a delicious idea.
This recipe can be easily doubled and baked in a 9x13 pan.
My mom likes to store it in the fridge, but it's delicious stored at room temperature as well!