NaturesAura/src/main/resources/data/naturesaura/recipes/ancient_slab.json

{
    "type": "minecraft:crafting_shaped",
    "pattern": [
        "WWW"
    ],
    "key": {
        "W": {
            "item": "naturesaura:ancient_planks"
        }
    },
    "result": {
        "item": "naturesaura:ancient_slab",
        "count": 6
    }
}