Grease every curve of the Bundt pan with butter or non-stick spray. Dust lightly with flour to prevent sticking.
Preheat oven to 350°F (175°C).
In a bowl, whisk flour, baking powder, baking soda, and salt.
In another bowl, beat sugar and eggs until pale and smooth.
Add oil (or butter), milk, and vanilla extract.
Gradually mix in dry ingredients.
Gently fold in peaches.
Pour batter evenly into the prepared pan. Bake for 50–60 minutes, or until a toothpick inserted into the centre comes out clean.
Cool for 15 minutes before turning out onto a rack.