Skybuilders' Oven

Taken all the way down to base materials, one Skybuilders' Oven is 2 crafting steps deep and needs 1 intermediate — Bluespirit Tile ×1 — which resolves to 5 distinct raw materials totalling 29 units, plus 13 crystals.

That bill outweighs 10,170 of the 13,602 recipes tracked here and 1,176 of the 1,932 Blacksmith ones, and 4,464 recipes nest deeper.

Only 6 of those crystals go into the final step; the other 7 are burned by the intermediates, so the real crystal cost is 11 Fire Crystal and 2 Earth Crystal.

Every step is Blacksmith work, from a Lv 74 intermediate up to the Lv 80 finish, so one class covers the whole chain.

All 5 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, Bluespirit Tile has the widest use: 72 recipes call for it, spanning six of the eight crafting classes.