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

In a large bowl, beat the softened butter and granulated sugar until light and fluffy, about 2-3 minutes. Add the eggs and vanilla, mixing until smooth.

In a separate bowl, whisk together flour, baking powder, salt, and cinnamon. Gradually add this to the butter mixture, alternating with milk, until just combined.

Fold in the chopped peaches carefully, ensuring they are evenly distributed.

In a small bowl, mix together brown sugar, flour, oats, ground cinnamon, and melted butter until crumbly for the topping.

Spoon the batter into cupcake liners, filling each about two-thirds full, and sprinkle the crumb topping generously.

Bake for 18-20 minutes or until golden brown and a toothpick comes out clean.

Allow the cupcakes to cool in the pan for about 5 minutes, then transfer them to a wire rack to cool completely.