In a mixing bowl, combine the flour, sugar, baking powder, and salt. Whisk until thoroughly mixed.
In another bowl, whisk together the milk, egg, and melted butter until well combined.
Pour the wet ingredients into the dry ingredients and stir until just combined. Be careful not to overmix; the batter should be slightly lumpy.
Gently fold in the diced peaches, ensuring they are evenly distributed throughout the batter.
Heat a large skillet or griddle over medium heat and grease it lightly with butter or non-stick spray.
Using a ladle, pour about ¼ cup of pancake batter onto the skillet for each pancake.
Cook until bubbles form on the surface of the pancake, about 2-3 minutes. Flip the pancake and cook for an additional 2-3 minutes, or until golden brown.
Repeat with the remaining batter, greasing the skillet as necessary.
Serve warm with maple syrup drizzled over the top.