[unverified]
“One of my mothers tricks to chicken she taught me was to ‘marinate’ chicken in seasoned buttermilk for 30 minutes or so before frying them.
“This allows the buttermilk to tenderize the meat – you do not NEED to do this but my mother recommends it.
“The chicken comes out juicy and tender with lots of flavor.”
https://myincrediblerecipes.com/copycat-popeyes-chicken-homemade/
That’s how Samin Nosrat does roast chicken:
https://www.saltfatacidheat.com/buttermilkmarinated-roast-chicken