Preheat the Oven:

Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat to prevent sticking.

Prepare the Cookie Dough:

In a medium bowl, whisk together the flour, baking soda, cinnamon, and salt. Set aside.

In a large bowl, beat the softened butter and granulated sugar together until light and fluffy, about 2-3 minutes. Add the egg and vanilla extract, beating until combined.

Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Stir in the sour cream, followed by the diced peaches. Be careful not to overmix to keep the peaches intact.

Shape the Cookies:

Using a cookie scoop or a tablespoon, drop spoonfuls of dough onto the prepared baking sheet, spacing them about 2 inches apart. These cookies will spread a little, so give them enough room.

Add the Topping:

In a small bowl, mix together the brown sugar, cinnamon, and granulated sugar. Sprinkle the sugar mixture over the top of each cookie dough mound for a sweet, slightly crunchy topping.

Bake the Cookies:

Bake for 12-15 minutes, or until the cookies are golden around the edges and set in the center. The peaches will caramelize slightly, adding to the cookie’s sweetness and flavor.

Cool and Serve:

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. Optional: Dust with powdered sugar and add extra chopped peaches on top for a fun garnish!