Preheat oven to 350°F. Spray a 10-inch bundt pan with nonstick cooking spray and set aside. (My 10-inch bundt pan is 3 inches deep. There should be at least 1 ½ inches between the height of the batter and the top edge of the pan.)
In the bowl of a stand mixer with a paddle attachment, beat the butter until smooth.
Gradually add the sugar and mix until light and fluffy.
Add the eggs, one at a time, mixing well after each addition. Add vanilla. Scrape down the sides of the bowl as needed.
In a separate bowl, whisk together flour, salt, and baking soda.
On low, beat in the flour mixture alternately with the sour cream, beginning and ending with the flour mixture.
Add the diced peaches and fold them in by hand.
Pour batter into the prepared bundt pan, filling it about ¾ of the way full. Bake for 1 hour 20 minutes to 1 hour 30 minutes. (The cake is done when a toothpick inserted into the center of the cake comes out with a few crumbs, but no wet batter. Do not underbake - you want a golden-brown crust.)
Allow cake to cool in the pan for 10-15 minutes before inverting it onto a plate to let it cool completely.