Pinecone is a resource in Genshin Impact that will grow in the wild in both Mondstadt and Liyue. It can be used in cooking, and more recently is needed for Liben during the Marvelous Mysteries event.
There are quite a few places in the game that make good spots for Pinecone farming, and it’s worth gather up as it will be needed to make Mondstadt Hash Brown, Sauteed Matsutake, and Puppy-Paw Hash Brown. You will need two for each dish.
Qingce Village Bridge in Liyue
The bridge in Qingce Village is always covered in Pinecones, as it seems the squirrels like to put them there. You should be able to find between 5 and 10 of them here.
Cape Oath in Mondstadt
To the north of the teleporter on Cape Oath, you can find a lot of pine trees with a near-endless supply of pinecones under them. This is also a great spot to farm Electro Crystals and some Iron Ore, so it is worth visiting regularly.
Both those areas, visited every couple of days, should keep you well stocked up on Pinecones.