Grease the baking tin with the buter and olive oil (be careful to use a not-too-deep and rectangular baking dish. In epirus, a baking tin especially for pies can be found - called sini). Place the tin in the oven to heat it up.
Meanwhile, make the pie mixture. Mix all the ingredients togeher (except for one egg, and the butter, if using). Add the cheese last, crumbling it. Pour the porridge-like mixture into the baking tin. Add pieces of cheese, pieces of butter, and the egg, beaten. Bake at maximum temperature in the oven for 50 minutes to 1 hour (depending on the oven). The pie is ready when the edges are very well baked.
In Wallach language, "kasiou" means cheese. Kasiopita is also called flour pie (alevropita) or kousmeri or zarkopita ("naked pie, i.e., without filo"). We have Lila's recipe, as written y Yiorgos Pittas at www.greekgastronomyguide.gr.