You know, clarified butter. It’s been melted, had most of its water boiled away. Won’t that work in a pie crust instead of butter, lard or shortening? Unfortunately not. For it’s the structure of butter, not merely its composition, that determines the way it behaves in pie crust.
Milk fat occurs not as a mass of lipid molecules with a few water molecules mixed in, but in pure lipid blobs, each of which is surrounded by a protein coat. It’s those protein-enclosed blobs, plus water, that create the emulsion that is butter. Destroy those blobs and what you get is a greasy slurry.
That’s exactly what happens with you melt and simmer butter. The proteins that enclose the fat blobs curdle in the sustained heat. They curl up, agglomerate and sink. This can be delicious (see: browned butter) but it’s no good for a pie crust. Why? Because it’s the small pockets of semi-firm butter in the dough that create flakes. Without them them you get a hard and greasy crust. So, good thinking readers Mike and Rainey! But a ghee crust just isn’t in the cards.