In a large bowl, add flour, sugar, baking powder, and salt, and stir to combine.
In a medium bowl, add egg, vanilla extract, melted butter, and milk, and whisk to combine.
Make a well in the middle of the flour mixture and pour the wet ingredients into the well. Using a spatula, gently mix the dry ingredients into the wet ingredients until no flour streaks remain but there are still plenty of lumps.
Once the batter is mixed, add the diced peach, and gently fold it into the batter being careful not to over-mix it.
Heat a griddle, skillet, or pan to medium heat, add a knob of butter, and allow to melt. Working in batches, add a 1/4 cup of the batter to the griddle, skillet, or pan and cook until bubbling on top, flip and cook for an additional 1-2 minutes per side until golden brown. Continue this process until all the batter is done. You can store the cooked pancakes on a baking sheet in the oven at 200°F to keep them warm.
Optional: While the pancakes are cooking, prepare the peach topping. In a small pan on medium heat, melt the butter, then add the sliced peaches and cook for 1-2 minutes per side until the peaches are tender and lightly browned. Once softened, drizzle in the maple syrup, and allow it to cook for an additional 1-2 minutes, stirring to coat the peaches. Once complete, turn off the heat and set it aside.
Once complete, serve the pancakes with peach topping and/or additional maple syrup.
Any leftover pancakes can be cooled completely and stored in an airtight container in the fridge for up to 5 days or in the freezer for up to 3 months.