Cassava Roll

2 cups cooked mashed cassava
2 T scallion oil
8 red lettuce leaves
1/3 cup mint or basil
1 green apple (optional), cut into match-stick strips
12 rice papers (6 inches)
salt, sugar

How to boil cassava:
Make a vertical slit on cassava tuber's skin, deep enough to see to white meat. Soak in water for 1 hour. Peel off the skin with your hands or with a knife. It should come off easily. Change water and soak for another hour.
Boil cassava in lots of water for 20-30 minutes, until soft. Discard water and remove inner core, don't use this water because cassava contains the potentially toxic compounds, cyanogenic glucosides which can cause acute cyanide poisoning. Mash cassava with a wooden spoon.
Mashed Cassava with scallion oil:
Season scallion oil with some salt and sugar, add to mashed cassava and mix well.
Make a roll:
Roll cassava mixture with lettuce, mint or basil, and green apple strips. Dip with sweet and sour fish sauce