Preheat your oven to 350°F (175°C) and grease a 9×13 inch baking pan.

In a large bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

In another bowl, combine the flour, baking powder, salt, and cinnamon.

Gradually add the dry ingredients to the butter mixture, alternating with the milk, until just combined.

Fold in the sliced peaches gently, ensuring their lovely flavor gets evenly distributed.

Pour the batter into the prepared baking pan and spread evenly.

Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for a few minutes, then transfer to a wire rack to cool completely.

Dust with powdered sugar before serving.