Bring water and pandan leaves to a boil in a deep saucepan. Add combined sugar and agar-agar powder. Stir well to dissolve. Boil for 2 to 3 minutes.
Add thick coconut milk and lower heat slightly. Bring to a gentle boil. Turn off the heat.
Beat egg whites till just stiff. Add vanilla essence. Stir in meringue or beaten egg whites to the agar-agar solution in batches. Divide agar-agar mixture into two equal portions. Add colouring to each portion.
Prepare a water-bath (basin with plenty of ice-cubes and water). Chill a tin (22cm x 15cm) in the water-bath. Pour half portion of red colour agar-agar mixture into the tin.
When about to set, take the tin out and slowly add half the portion of orange colour agar-agar over. Return the tin to the water-bath to set the second layer. Add two more layers the same way. When set, chill the agar-agar well before cutting to serve.