Wash the enoki mushrooms, cut off the root, and slice them into bite-sized pieces.
Julienne the onion and bell pepper.
Heat cooking oil in a pan and sauté the onion.
Add the enoki mushrooms and bell pepper, then stir-fry together.
Season with soy sauce, oligosaccharide, and pepper.
Spoon the stir-fried enoki mushrooms and vegetables over rice.