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

In a large mixing bowl, cream together softened unsalted butter and granulated sugar for about 3-4 minutes until light and fluffy.

Add the large eggs one at a time, mixing until fully incorporated, then blend in the vanilla extract.

In a separate bowl, whisk together all-purpose flour, baking powder, salt, and ground cinnamon.

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

Gently fold in the sliced fresh peaches into your batter.

Pour the batter into the prepared baking dish and bake for 30-40 minutes.

Let the cake cool in the pan for 10-15 minutes before slicing and serving.