Trim the root of enoki mushrooms and cut them into bite-sized lengths. Slice the onion thinly.

Rinse the peeled shrimp under water and pat dry with kitchen paper.

Boil water in a pot, add salt (not listed in ingredients) and cook spaghetti 1 minute less than package instructions. Drain well.

Heat butter in a frying pan over medium heat. Add onion and enoki mushrooms, sauté until softened. Add shrimp and stir-fry quickly until they change color.

Add flour and stir until no longer powdery. Gradually add milk, stirring constantly over low heat until thickened. Season with salt and pepper.

Add cooked spaghetti to the sauce and mix well to coat evenly.