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

{
  "type": "crafting_shaped",
  "pattern": [
    "##"
  ],
  "key": {
    "#": {
      "item": "minecraft:iron_ingot"
    }
  },
  "result": {
    "item": "minecraft:heavy_weighted_pressure_plate"
  }
}