Steel Plate

Taken all the way down to base materials, one Steel Plate is 2 crafting steps deep and needs 1 intermediate — Steel Ingot ×2 — which resolves to 2 distinct raw materials totalling 6 units, plus 7 crystals.

That bill outweighs 4,542 of the 13,602 recipes tracked here and 466 of the 1,441 Armorer ones, and 4,464 recipes nest deeper.

Only 3 of those crystals go into the final step; the other 4 are burned by the intermediates, so the real crystal cost is 4 Fire Shard and 3 Ice Shard.

The chain crosses two disciplines — Armorer to Lv 27 and Blacksmith to Lv 26 — so no single class can finish it unaided.

Both raw materials are gathered, and no spot for either is timed, so nothing in the tree waits on the Eorzean clock.

Steel Plate is itself consumed by 57 further recipes, spanning six of the eight crafting classes.