To obtain the recipe for the Sword of Snow-Tombed Starsilver, you need to find 8 tombstones with an ancient inscription in the Dragon Ridge location

Map with all the tombstones

To activate this tombstone, you need to complete In the Mountains

To activate this tombstone, you need to complete Secret room

At the end, after opening the chest, do not forget to light all 4 torches, this way you will receive the sword Snow-Tombed Starsilver