- Preheat oven to 350°F (175°C). Grease and flour a Bundt pan.
- In a bowl, whisk together flour, baking soda, baking powder, and salt.
- In a large bowl, cream butter and sugar until light and fluffy. Add eggs one at a time, beating well after each addition.
- Mix in vanilla and sour cream.
- Gradually add the dry ingredients to the wet, mixing just until combined. Fold in peaches and optional cinnamon.
- Pour batter into the prepared Bundt pan and bake for 50-60 minutes, or until a toothpick comes out clean.
- Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
For the Brown Butter Icing:
- In a saucepan, melt butter over medium heat, stirring constantly until it turns golden brown and develops a nutty aroma.
- Remove from heat and let cool slightly.
- Whisk in powdered sugar, milk, and vanilla until smooth. Drizzle over the cooled cake.