It's tuna cutlet. You don't seem to get a reward for giving it to him, he just says to buy some from him next time you are by. Maybe he will stock more tuna in the future?

<t>Some more combos:<br/> <br/> tofu miso soup +  many rice dishes<br/> <br/> Nonalcoholic drinks + pizza  or parfait or bunny apple<br/> <br/> Any tea + any toast + most types of egg ( or any 2 of 3)<br/> <br/> Alcohol plus deep fried foods or smoked foods<br/> <br/>  <br/> <br/> Haven't managed to...