Rinse the frozen shrimp under water until they soften on the outside.

Bring a pot of water to a boil and add the udon noodles. Cook according to the package instructions. If the noodles finish cooking too early, transfer them to cold water to prevent overcooking.

In a separate skillet, add a little water and the clams. Cover with a lid and steam until the clams open.

Add the shrimp, water, Japanese soy sauce, and white soup stock to the skillet. Add the soy sauce first so you can better adjust the flavor. Cook until the shrimp are done, then remove from heat.

Top with sliced green onions for a nice presentation.