Preheat your oven to 350°F (175°C) and line a cupcake pan with paper liners.

Cream together the butter and granulated sugar on medium speed for about 2-3 minutes until light and fluffy. Add the eggs one at a time, mixing after each addition, then stir in the vanilla extract.

In a separate bowl, whisk together the all-purpose flour, baking powder, salt, and ground cinnamon. Gradually mix this into your wet mixture, alternating with milk.

Gently fold in the chopped fresh peaches until evenly distributed throughout the batter.

Combine rolled oats, brown sugar, flour, cinnamon, and melted butter in a small bowl, mixing until it resembles coarse crumbs.

Fill cupcake liners about two-thirds full with batter and sprinkle the crumb mixture generously over each cupcake.

Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean. Let cool in the pan for 5 minutes before transferring to a wire rack.