MineAssets/1.12.2/assets/minecraft/recipes/iron_ingot_from_block.json

{
  "type": "crafting_shaped",
  "group": "iron_ingot",
  "pattern": [
    "#"
  ],
  "key": {
    "#": {
      "item": "minecraft:iron_block"
    }
  },
  "result": {
    "item": "minecraft:iron_ingot",
    "count": 9
  }
}