01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, baking soda, and salt. Set aside.
03 - In a large bowl, beat butter, granulated sugar, and brown sugar until light and creamy, about 2 minutes.
04 - Add eggs one at a time, beating well after each addition. Mix in vanilla extract and sour cream until combined.
05 - Gradually add the dry ingredients to the wet mixture, mixing just until incorporated.
06 - Gently fold in white chocolate chips and diced peaches.
07 - Drop dough by rounded tablespoonfuls onto prepared baking sheets, spacing 2 inches apart.
08 - Bake for 11 to 13 minutes, or until edges are golden and centers are set.
09 - Let cookies cool on baking sheets for 5 minutes, then transfer to a wire rack to cool completely.