This is an old favourite of mine and you'll find other copies of this build on the site from old accounts I no longer have access to.
The Iron onion is prepared to make use of the Iron Flesh pyromancy, making up for the slow movement with the Golem Axe's special attack and the havelin's powerful shots. In case slow tanking isn't an option, Power within allows to turn into a faster moving berserker onion to turn the whole playstyle around. Great fun for PVE and can get some good results in non-tryhard pvp.