Slice the mushrooms and sauté them with lemon juice, salt, pepper, and a little oil until all the excess moisture has evaporated.

Drain the oil from the canned tuna, transfer the tuna to a large bowl, and gently break it into smaller pieces.

Add the sautéed mushrooms, chopped walnuts, cooked sweetcorn, salt, pepper, and your preferred salad dressing or mayonnaise. 1. Mix everything thoroughly until well combined.