Simmer dashi, soy sauce, mirin, monk fruit, and ginger in a wide pan
Add onions and simmer until they start to soften
Add the brisket slices and simmer until just tender (about 3-5 minutes)
Remove the beef and onions and set aside
Add the Napa cabbage into the remaining sauce, cover and steam/simmer until soft and flavor-packed
Layer ½ cup rice, then cabbage, then beef on a plate
Top with a 7-minute soft-boiled egg
