Note: this recipe will make more taro paste than needed. You can refrigerate or freeze the rest of the paste for future use.
Cut the taro into cubes and boil the taro in a pot, covered, with 1/2 cup water until the water has mostly evaporated and the taro is fork tender.
Using a food processor, blend the taro with sugar until it is a smooth paste. The consistency should be similar to apple sauce. It is okay if it is a bit wetter or dryer, we can adjust this in the next step.
Transfer the taro paste to a skillet and cook on medium-low heat, stirring constantly until the taro paste consistency is similar to mashed potatoes. If the taro paste is too dry, you can add more water. Near the end of cooking, mix in the canola oil. This will give the taro paste a smooth mouthfeel and a glossy finish.
Transfer the taro paste to a bowl, cover with plastic wrap, and let it cool completely.
Once cooled, weigh out 4g of taro paste and roll it into a ball. Repeat 25 times. Wrap the taro balls in plastic wrap and refrigerate while you prepare the shortbread.