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

{
  "type": "minecraft:crafting_shaped",
  "pattern": [
    "###",
    "# #",
    "###"
  ],
  "key": {
    "#": [
      {
        "item": "aether_legacy:skyroot_plank"
      }
    ]
  },
  "result": {
    "item": "minecraft:chest"
  }
}