Pumpkin/assets/datapack/data/minecraft/recipe/black_cushion.json

{
  "type": "minecraft:crafting_shaped",
  "group": "cushion",
  "key": {
    "#": "minecraft:black_wool_slab"
  },
  "pattern": [
    "###"
  ],
  "result": {
    "id": "minecraft:black_cushion"
  }
}