I use frozen grated ube sold in Asian grocery store. I thaw it and discard any excess water after thawing. Steam it for 15 minutes until they are easily mashed. Put in a food processor and blend until smooth
Prepare the batter:
Line an 8 x 8 square pan or 9-inch round pan (for full recipe) or 8 x 4 loaf pan (for half recipe) with banana leaves. Brush the leaves with oil to prevent sticking. If you don't have banana leaves, you can use parchment paper
Prepare a steamer by bring the water to a boil and then lower it to medium to let it simmer while you are preparing the batter
Combine the mashed ube with coconut milk, and sugar. Whisk to combine. Add the glutinous rice flour and whisk again to combine. Strain the batter if necessary to get rid of the lumps or if you don't mind a bit of tiny pieces from the ube, you can leave them as is
Steaming:
Pour the batter into the prepared pan. Wrap the lid of the steamer with a cloth to prevent water condensation from dripping on the cake surface. Put this into the steamer and steam over medium-high heat for 55-60 minutes or until toothpick inserted comes out clean with few sticky crumbs is ok as long as it's no longer wet
Cool down:
Let the cake cool down completely at room temperature. Cut into small serving size. Top each piece with latik and serve