Cut open the mentaiko and extract the contents.

Slice the daikon into thin strips after cutting it vertically into 1cm-wide pieces.

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

Heat olive oil in a frying pan over medium heat and sauté the daikon until tender.

Add mentaiko, soy sauce, pepper, and butter to the pan and stir quickly. Then add the spaghetti and mix well.