Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish.
In a large bowl, whisk together the flour, baking powder, salt, and granulated sugar.
In another bowl, mix the milk, melted butter, egg, and vanilla extract until well combined.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Turn the dough out onto a floured surface and roll it into a rectangle about 1/2 inch thick.
Spread the chopped peaches evenly over the dough.
In a small bowl, mix the brown sugar and cinnamon together, then sprinkle it evenly over the peaches.
Starting from one long side, carefully roll the dough into a log. Slice the log into 1-inch thick rolls.
Place the rolls in the prepared baking dish, leaving a little space between each roll.
Bake for 25-30 minutes or until golden brown.
While the rolls are baking, prepare the glaze by mixing the powdered sugar and 1 tablespoon of milk until smooth.
Once the rolls are done, drizzle the glaze over the warm cinnamon rolls and serve.