Prepare the shimeji mushrooms by trimming the roots and separating them into bite-sized pieces. Slice the onion thinly along the grain.

Heat half the butter (10g) in a pan, add breadcrumbs, and toast over low heat until golden brown. Remove and set aside.

In the same pan, add the remaining butter (10g) and sauté the onion and shimeji mushrooms over medium heat for about 3 minutes until softened. Add macaroni and water, bring to a boil, cover, and simmer for the time indicated on the macaroni package. Remove the lid and cook over medium-high heat to evaporate excess water. Stir in flour until fully incorporated.

Reduce heat to low and gradually add milk in three portions, stirring after each addition. Add the seasonings (sake, salt, pepper, consomme) and shrimp, cooking until the shrimp are fully cooked and the mixture thickens.