Steam the Vegetables: Steam the peeled taro and purple sweet potato in a pot for 20-30 minutes, until you can easily poke through them with chopsticks.

Blend the Paste: Once steamed, place the taro and purple sweet potato into a blender or food processor. Add the condensed milk, butter, and sugar, and blend until smooth. A few lumps are fine, as they’ll dissolve during cooking.

Cook the Paste: Transfer the blended mixture into a non-stick pan. It’s important to use a non-stick pan and keep the heat low.

Stir and Cook: Stir constantly while cooking the paste. Cook until it no longer sticks to the pan or spatula and can form a cohesive mass. At this point, the paste is ready.

Cool and Store: Place the cooked taro paste into a container, cover the surface with plastic wrap, and let it cool.

Refrigerate: Once completely cooled, store it in the refrigerator. The paste will firm up and become more moldable, making it perfect for shaping.