To add it to your Adventurer's Lost Ark Gold Tome, simply click it in your inventory after purchasing.

Split image of player beside barrels of Regria Monastery and map of Rethramis Border

The clue to finding this recipe is found in the name itself. There is Regria Flower Oil in the Rethramis Border area, just in front of the southwest entrance to Regria Monastery. Regria Monastery.

Approach toward the Border Guards here, standing in front of a barricade with spikes. To to the left , to the left, there are several wooden barrels. Engaging with them will help you draw Regria Flower Oil. Regria Flower Oil.

Left to Right: a man standing in front of windmill in Rethramis Border, map of Rethramis Border, cooking menu together with Cook Hely

The good news is that your next Rethramis Cooking Recipe can be found within the Rethramis Border area. Travel north, to Wind Road. On the topmost point of the area, in some boulders hidden by a windmill, there is an icon for Investigate. Interact with it to collect a Solar Tree Sprout. But you aren't done but you are not quite done.

Now you must travel back to Lost ark gold buy Prideholme and travel to Cook Hely, found just to the left of Rapport NPC Siera. There you can make an alcoholic beverage called Solar Tree Sprout Cider for the price of 900 silver.