Slice the mochi into 2-3mm. I got 15 slices out of 1 cake.
Scatter the mochi in a non-stick pan (18 cm diameter). Don't let the mochi slices overlap. No oil necessary.
Heat over medium heat. After 1 minute, the mochi will start to puff up a bit. The mochi pieces can get stuck together or stay apart with gaps in between at this point.
Top with the shredded cabbage, and pour in a beaten egg. Drizzle water along the perimeter of the pan, cover with a lid and cook over medium heat for 3 minutes.
When the cabbage has wilted, it's done. Take a peek at the bottom by lifting up the pancake with a spatula. If the mochi is crispy, it's good.
Turn off the heat, and drizzle on the mayonnaise and sauce while it's still in the pan. They'll sizzle up a bit and add more flavor.
Top with bonito flakes and it's done! It tastes like a proper okonomiyaki.
Story Behind this Recipe
I got the idea for this from mochi pizza, and used some cabbage and and egg only for a really inexpensive meal. This is a simple recipe.
Even if the mochi pieces don't stick together at Step 3, it's fine. The egg added in Step 4 will stick the mochi and cabbage together. You can add a ton of cabbage and it will be OK. It will shrink when it's steamed. If you are using a cast iron pan, you need to add vegetable oil.