Boukensha Sakaba no Ryourinin

Yoishi the tavernkeeper has a big problem with adventurers...because they have awful diets! One day, some rookie adventurers happen to bring back the bitter stone walnut from the dungeon, considered by many to be inedible. Hoping to find a way to incorporate it into a new dish, Yoishi taps into his knowledge of previous eras and embarks on a new culinary adventure!

(Source: Yen Press)