Once I had been to the cave just after visiting the village of Roysburg for the first time, I came back to Roysburg. I went into the first house in the top right of the village and one of the women in here asked for some ingredients. When I gave her them, she made Horse Oak Casserole and gave me 1 plus the recipe so I could buy more from any cook. Upon eating the Horse Oak Casserole, I unlocked this trophy.
I already had the ingredients by this point, so if you are missing some, then I am not much help as I don't remember the specifics. However, this guide may be of use. It tells you where all the shiny points on the map are
http://teambrg.com/i-am-setsuna/setsuna-shiny-spots-location... If you want to get them all then you can compare it with the 'Snow Chronicles > Locations' section in the games menu