Preheat oven to 350. Spray a 9X13 baking dish with non stick spray
In a medium bowl combine brown sugar and nutmeg. Mix well.
In a large bowl, mix peaches with 1/2 of the sugar/nutmeg mixture. Toss well to coat. Set aside for about 30 minutes to let the peaches soak up the sugar and make juice.
In another large bowl, combine the flour, baking powder, salt and remaining brown sugar mixture.
In a separate bowl, mix together the milk, eggs, vanilla, lemon zest and melted butter. Whisk until well combined.
Slowly blend the milk mixture into the flour mixture until the batter is smooth.
Evenly spread the peaches in prepared baking dish. Evenly spread the batter over the top of the peaches and bake until the batter becomes golden brown - about 30-35 minutes.
Remove from oven and let sit for 30 minutes before serving. Scoop into 12 equal servings. Serve warm or at room temperature.