Ratatouille

Taken all the way down to base materials, a batch of 3 Ratatouille is 2 crafting steps deep and needs 1 intermediate — Lavender Oil ×1 — which resolves to 6 distinct raw materials totalling 9 units, plus 9 crystals.

That bill outweighs 5,492 of the 13,602 recipes tracked here and 644 of the 1,058 Culinarian ones, and 4,464 recipes nest deeper.

Only 8 of those crystals go into the final step; the other 1 are burned by the intermediates, so the real crystal cost is 5 Fire Shard and 4 Water Shard.

Every step is Culinarian work, from a Lv 16 intermediate up to the Lv 37 finish, so one class covers the whole chain.

All 6 raw materials are gathered, and not one of their spots is timed, so nothing in the tree waits on the Eorzean clock.

Of the intermediates, Lavender Oil has the widest use: 5 recipes call for it, spanning four of the eight crafting classes.