In a large bowl mix the 2 types of flour. Heat the butter in a saucepan with a thick bottom and add the flour.
Stir over low heat so as not to burn, until golden brown.
Remove from heat and set aside. In another pan, mix the sugar with the water and milk and bring to a boil.
Reduce the heat and simmer until a thick syrup is formed.
Remove from the heat and add the flour mixture. Finally stir in pistachios, while whipping constantly.
Spread the mixture onto a buttered tray and then rake it thoroughly. Cut into equal squares.