Slice the king oyster mushroom thinly and chop the komatsuna into 3cm pieces. Mince the garlic after removing its core.

Heat olive oil, garlic, and red chili in a pan over low heat until fragrant. Add the mushrooms and komatsuna, then stir-fry over medium heat until softened. Add the saba canned fish with its juice and cook for 1-2 minutes.

Boil water in a pot, add salt (not listed in ingredients), and cook the spaghetti according to package instructions. Drain the water.