So basically, i was making a huge custom desert temple and when it got to the roofs I thought of the roofs ive seen on churches and such, i did a little research and found out they were called onion domes. However, when I searched for how to make them I wasnt able find any tutorial whatsoever. Through some trial and error i found that an extremely effective method to making them is to use worldedit and to do //sphere, dig roughly halfway into the sphere from above and then do //cone sphere size for diameter and roughly
1.5x the size of the sphere for the hight and you will get a great onion dome!