In a large mixing bowl, combine all-purpose flour, dashi stock, and beaten eggs until smooth, stirring in tempura scraps. Allow to rest for about 5 minutes.

Generously coat a takoyaki pan with oil over medium to medium-high heat until shimmering.

Pour the prepared batter into each mold, filling them about three-quarters full.

Drop small pieces of cooked octopus and chopped green onions into each mold evenly.

Let cook for 2-3 minutes, then gently flip using two picks or skewers.

For extra crunch, sear cooked takoyaki on a hot griddle for 1 minute.

Transfer to a plate, drizzle with takoyaki sauce and mayo, then sprinkle with bonito flakes and aonori before serving.