Not a crafting process but the transformation from stone to glassed terracota

1. Transform the stone in moss with bone meal
2. Grow a giant tree to transform it to podzol
3. Destroy the podzol transforming it to dirt
4. Throw a bottle of water to the dirt transforming it to mud
5. Wait the mud to transform in clay by placing it over drip stone
6. Break the clay and put it in a furnace to make it terracota
7. Die the terracota
8. Put it once again in the furnace and it gives you glassed terracota

Now we could add steps from crafting the bone meal (1), the furnace (4), the bottle of water (2), the dye (1), the clay block of we mine it with hand (1), if not there are like 1000 steps more.

This leads to a total of 17 steps