Grease two standard sized loaf pans or 4 mini loaf pans.
Mix oil, peanut butter, and sugar in a large bowl with a stand mixer whisk.
Add the bananas, eggs, sour milk, and baking soda to the peanut butter mixture.
Beat until combined.
Slowly mix in flour, beating just until combined, don't over mix!
Mix in the crushed Oreos. Divide the batter evenly between the two pans (even if it looks like the batter could all fit comfortably in one pan, don't! it won't bake all the way through without burning the outside in one pan).
Crumble the 6 Oreos over the batter (3 Oreos for each pan).
Bake for 30-35 minutes or until toothpick inserted comes out mostly clean (it IS a very moist bread, so you may still have a little bit of bread that sticks to the toothpick, that's ok).
Let cool for at least 10 minutes in the pans before removing and cool completely before sliceing.