minecraft-assets/data/minecraft/recipes/carrot_on_a_stick.json

{
  "type": "crafting_shaped",
  "pattern": [
    "# ",
    " X"
  ],
  "key": {
    "#": {
      "item": "minecraft:fishing_rod"
    },
    "X": {
      "item": "minecraft:carrot"
    }
  },
  "result": {
    "item": "minecraft:carrot_on_a_stick"
  }
}