In a small bowl, combine the diced peach with 1 tablespoon brown sugar. Let rest for 15 minutes to release the juices.
In a larger bowl, whisk together the remaining sugar, flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
Add the buttermilk to a measuring cup and crack in the egg. Mix with a fork until well combined.
Add the wet ingredients and peaches to the dry ingredients and stir just until the dry ingredients are moistened. Next, stir in the melted butter. Let the batter rest for 15 to 30 minutes.
Heat a griddle or cast iron skillet over medium heat. Add a tablespoon of butter to the hot griddle and spread it around to coat the surface. The butter should sizzle, but not burn!
Pour 1/4 cup batter for each pancake onto the griddle. Cook until the surface bubbles and the bottom is golden brown, about 3 to 4 minutes. Flip and cook another 2 - 3 minutes until the surface is springy and the bottom is golden brown. Transfer to a plate and repeat with the remaining batter.
Serve warm with maple syrup and more peach slices and berries, if desired.
Don't over mix the batter. Too much stirring and the gluten develops which is good for bread, but not so much for pancakes. Only stir to wet the ingredients, otherwise you may end up with tough pancakes
Let the batter rest. As the batter rests, the gluten will relax a bit and the batter will get thic
Use room temperature ingredients. The eggs and milk will get more evenly distributed if they're not straight from the fridge and ice cold. Even when you melt butter for the batter, let it cool a bit before you add it in
Only flip the pancakes once. Once the surface bubbles up all over, gently lift one edge to check that the pancake is golden brown. Carefully flip and cook the other side, but don't flip back and forth or you'll flatten the pancakes.