Dice the potatoes and sweet potatoes.
Cut the carrot and onion into bite-size pieces.
Add potatoes, sweet potatoes, and carrots to a pot and pour in enough water to cover them.
Add soy sauce, sugar, oligosaccharide, and minced garlic, then bring to a boil.
Once boiling, reduce to medium heat and add onion and green onion.
Simmer until the sauce is slightly reduced.
Finish with sesame oil and toasted sesame seeds.