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

{
  "type": "minecraft:crafting_shaped",
  "category": "building",
  "key": {
    "A": {
      "item": "minecraft:carved_pumpkin"
    },
    "B": {
      "item": "minecraft:torch"
    }
  },
  "pattern": [
    "A",
    "B"
  ],
  "result": {
    "item": "minecraft:jack_o_lantern"
  }
}