The Mushroom Cake in Pokémon Legends: Arceus isn’t as accessible as most foods and berries you’ll find out in the wild. This is mainly because players will need to complete one of two requests in order to get multiple Mushroom Cakes at a time. The quests do pay off, as the item works as a throwable lure for more monstrous creatures, such as dragon Pokémon.
The fastest way to obtain at least one Mushroom Cake is from breaking the boxes near the waters of Cobalt Coastlands’ Sand’s Reach location. However, you can also complete Request 6, Mushroom Cake Marketing, in order to unlock its recipe. This can be started by speaking to NPC Morel near the Fieldlands Camp in Obsidian Fieldlands. With the recipe, you’ll be able to craft Mushroom Cakes with just one Springy Mushroom and one Cake-Lure Base.
Additionally, the item can be purchased at Jubilife Village’s General Store after Request 23, Getting Ahold of New Wares, is completed. This is given out from the General Store’s storekeeper, Choy, who will sell the Mushroom Cakes for 400 Poké Dollars once the request is finished. It is also worth checking which items Ginkgo merchant Ginter is selling outside of Galaxy Hall. It isn’t guaranteed that he will offer Mushroom Cakes, but if he does, he will offer 10 of them for only 2,000 Poké Dollars.