I've been following sweetrosie's "delectable gastronomy" blog for a while now. She's just shared a post on the use of blue colouring in food.
"Nyonya kueh, or cakes are a wonderful example of this attention to detail. These little darlings are made into shapes and parcels that say “EAT ME!” . A kueh platter is a kaleidoscope of delicious texture, shape and colour – pink, red, green, yellow and yes! Blue!"
Sweetrosie tells you more about "pulot tai tai", that yummy blue and white rice cake eaten with kaya. The blue colouring comes from the butterfly pea flower, although people have been known to use artificial colouring :-) A very similar kueh, "pulot inti", is described in my own post on Sunday Morning Snacks.
Sweetrosie's full blog post can be found here. Thanks so much Sweetrosie for helping promote one of the most yummy and unique cuisines of Southeast Asia!