Hello Vicki, no, they're not cut and come again. You can eat them any size you like but they don't get very big. I just cut them off at ground level. You can steam them whole, or divide into leaves and add to stir fries. Delicious either way. Sowing to eating is 4 to 6 weeks so just note how long they have been in the ground. Enjoy.
That's the Pak Choi about ready for eating just below the wooden contraption. And the ones beside them were planted 2 weeks ago.