Preheat oven at 200 degree C.
greased 9 inches pan, i made it in pudding pan.
seperate egg whites and yolks and beat egg whites untill soft peak forms, yolks set aside.
Beat oil and suger with electric beater untill light and fluffy.
add yolk 1 by 1.
add baking powder then baking soda then essence with modrate speed.
seave meda and coco powder 2 or 3 times.
add meda mixture in egg mixture in 3 batches at medium low speed.
in last mix egg whites in cake mixture with spatulla with light hand.
transfer into pan set mixture equally, and put it in the preheated oevn for 30 to 45 minuts (depanding on ur oven tamprature).
but check cake time to time with toothpic after 30 minuts,when done cool it on marble top.
mix milk,corn flour,suger,coco powder in sauce pan with wire wisk.
cook on midium low flam and wisk mixture contuniously untill become thick, about 4 to 5 minuts.
put off flam and mix butter and freash cream with wisk that it becom smooth and nice.let it be cool.
pour frosting on cake smooth from whole side, chop walnuts and spread on top. keep refrigrate for 3 to 4 hours.