src/main/resources/assets/aether_legacy/recipes/iron_ring.json

{
  "type": "minecraft:crafting_shaped",
  "pattern": [
    " I ",
    "I I",
    " I "
  ],
  "key": {
    "I": {
      "item": "minecraft:iron_ingot"
    }
  },
  "result": {
    "item": "aether_legacy:iron_ring"
  }
}