Defrost the seafood mix and drain excess water.

Chop the cabbage into coarse pieces. Cut the mochi into quarters.

Slice the mentaiko into quarters.

In a bowl, mix flour, dashi powder, and water. Add the egg, tempura flakes, and cabbage, mixing gently to incorporate air. Add the seafood mix and stir to combine.

Heat salad oil in a frying pan. Spread a small amount of batter into a round shape, place mochi and mentaiko on top, then cover with the remaining batter. Cook over medium heat until browned.

Flip the okonomiyaki, add pizza cheese on top, cover with a lid, and cook over low-medium heat until the batter is fully cooked.