Cut the spinach into 3cm pieces after removing the roots.

Remove the shrimp's vein, wash, and pat dry.

Boil water in a pot, add salt, and cook spaghetti 1 minute less than the package instructions. Drain.

Heat butter in a pan over medium-low heat, add shrimp, and cook until color changes.

Add spinach to the pan and sauté until wilted.

Add flour to the pan and stir until no longer powdery. Pour in milk, add salt and pepper, and simmer on low heat until thickened.