Blanch the napa cabbage to make them easier for the wrapping process: cut to around 1-2 inch each, and add to boiling water for about 1 min. Shock them in ice water before draining and removing that excess water.
Prep the sauce by combining all ingredients in a pot and simmering just until the sugar is dissolved. Let it cool on the side.
Prep the rolls: layer napa cabbage (outside) -> beef -> mushroom (inside). A pack of mushrooms makes about 12-13 bundles.
Tuck the rolls into a pan, add the sauce, cover with a lid, and cook for about 10-15 min at medium/medium-low heat.
Turn up the heat to medium-high and add in the eggs, cover the lid again and let it cook for about 1 min.
Garnish with green onions and enjoy with a hot, steaming bowl of rice.
