Buttermilk pie is sometimes confused with chess pie, but there are two major differences. Buttermilk pie is the only one of the two that uses buttermilk. Chess pie uses evaporated milk. Chess pie uses cornmeal for the thickener, while classic buttermilk pie uses flour. Both are rich and delicious, but if I had to pick one for the rest of my life, it would be buttermilk pie. I like the smooth tanginess from the buttermilk and find the flavor a bit more interesting.