In a large mixing bowl and with a whisk, add the buttermilk, melted butter, eggs, vanilla and brown sugar and whisk until smooth. Add the remaining ingredients and end by folding in the shredded zucchini. Heat a flat griddle or saute pan to medium-high heat. Butter the pan where you will pour the pancakes. Scoop about 1/2 cup of batter onto the hot griddle and cook. Let the bottom side of the pancake cook until golden brown and the bubble start to pop. Flip the pancake and cook on the second side. Serve with maple syrup and butter as desired.