I also make this mixture, but I use more butter than oil and add a spoonful of starch, which is the reliable method.
ﺣﺘﻰ ﺍﻧﺎ ﻧﺪﻳﺮ ﻫﺎﺩ ﺍﻟﺨﻠﻄﺔ ﻭﻟﻜﻦ ﻛﻨﻜﺜﺮ ﺍﻟﺰﺑﺪﺓ ﻋﻠﻰ ﺍﻟﺰﻳﺖ ﻭﻧﺪﻳﺮ ﻣﻌﻴﻠﻘﺔ ﺩﻳﺎﻝ ﺍﻟﻨﺸﺎﺀ ﻫﻲ ﺍﻟﻤﻌﺘﻤﺪﺓ