Okonomiyaki is a savory Japanese "pancake" or "pizza" that is originally from the city of Osaka, Western Japan in the Kansai region. It's popular throughout the country with many regional versions available. It's actually closer to a scallion pancake. I've made the original here.
TIP: You can purchase the Otafuku brand okonomiyaki batter mix at any Japanese supermarket,or you can make your own using the ingredients listed in the recipe.
Get the Otafuku recipe here.