In a large bowl, whisk the flour, seafood stock, eggs, salt, and black pepper to form a batter.
Fold in the chopped shrimp, shredded carrots, scallions, and shredded cabbage. Mix until the vegetables are fully coated in the batter.
In a medium (10-12 inch) skillet, heat a couple tablespoons of olive oil over medium heat, until shimmering. When the oil shimmers, pour the vegetable and shrimp mixture into the pan, including any remaining liquid (this will help form the pancake).
Cook on one side until browned, about 8 minutes.
While the pancake is cooking, whisk together the ketchup, oyster sauce, worcestershire sauce, and sugar to form the okonomiyaki sauce.
Flip the pancake and cook for an additional 5 minutes. When the pancake is set, use a few spatulas to lift it onto a plate as one piece.
Drizzle the top with okonomiyaki sauce, spicy mayo, and sesame seeds.
Slice and serve warm.