The second time Tom made the dashi, it was to get a key ingredient for Tai's cookies. Dashi simply was a by-product of his operation.
Despite Tom having some doubts originally, these cookies met with big approval by Tai. He is thrilled every time Tom starts making katsuo-nori cookies. His eyes twinkle and follow the movements of Tom's hands as if he knows exactly what comes next -- straining dashi, putting moist katsuobushi into a bowl along with crushed nori seaweed, mixing again, spooning on a baking sheet, and so on.
Making these cookies involves no exact measurement. All ingredients are simply mixed and allow to sit for a while (to let oats absorb moisture), and baked until the surface is crispy! The ingredients Tom uses are: large handful rolled oats, small amount of flour (to bind everything), some milk, katsuobushi from making dashi, and several sheets of nori seaweed.
Recipe for Tom: Katuo dashi, katsuo-kobu dashi / bonito stock, bonito-kelp stock