reached home, i quickly browse throught Alex Goh's Recipe book & search for this recipe. I replaced the butter with canalo oil as my mum don't eat butter. The cake turn to to be quite good. Not sweet (i reduced the amt of castor sugar), light fragrance of sweet potatoe, texture was soft but not as fine as expected & as usual, slightly dense at the bottom.
Since i got the time, i made the roti prata chicken pie again. This round, i cutted the flat dough into 3 pieces. the size of the folded pie was just nice. *-*