In a bowl, mix together all-purpose flour and water/dashi stock. Set aside and chill for about an hour.
Remove from the refrigerator and add in half of the SPAM® Classic cubes, cabbage, green onions, corn kernels, cheddar cheese, and tempura flakes. Mix thoroughly.
Add eggs into the batter and mix. About 1 egg for every 1/2 cup batter.
Heat a pan and bring to medium heat.
Pour in half cup of batter, creating a round shape. Cook until brown and crisp and flip to cook the other side. To check doneness, insert a toothpick at the center and pull it out. Clean toothpick means it’s cooked.
Transfer to a serving plate and brush with okonomiyaki sauce.
Drizzle with mayonnaise and garnish with remaining SPAM® Classic cubes and preferred toppings.