I've made a few by hand and it's very hard work, especially if the wood is not particularly green which doesn't help !
There was a time and effort saving removing the bulk of the waste with a forstner bit, I used a 1" or so size and several holes as the larger bits would just stall the drill press, and then gouges to finish.
Now I'm back up and running with my woodturning lathe I'm thinking of roughing the shape out on the bandsaw and turning the inside of the bowl on the lathe, and possibly doing the lower part of the outside on the lathe also. Will have to experiment a bit and see how it goes.
Not got the same entirely hand made ethos of course, of axing out the blank by hand and carving with gouges and knives, but I've done that too, and although very satisfying I probably wouldn't rush to do any more that way as it takes me ages and kills my hands !