In a small bowl or a 2 cup measuring cup, combine the milk and vinegar and set aside for 5 minutes to become buttermilk. Add the egg and melted butter to the buttermilk and using a whisk, beat lightly until mixed.

In a large bowl, mix together flour, salt, baking powder, and sugar. No need to sift. Add the grated zucchini and just give it a quick toss. Stir the milk mixture into the dry mixture only until combined. Do not overmix. Set aside for 10 minutes.

Heat a nonstick griddle or frying pan over medium-high heat. Drop a few drops of water to make sure the griddle is hot, the water should sizzle and evaporate. Pour or scoop the batter onto the griddle, using approximately ¼ cup for each pancake. Dot the pancakes with chocolate chips as preferred before flipping. Brown on both sides for about a minute per side. Serve warm.