Cut my onion tops today. They are the first thing you harvest and eat and I’ve been enjoying them since last month. If you cut them properly, you can harvest them several times.
What I do is wait until the greens are 9 or more inches tall (they taste better if not too big). Then cut the stalk a little less than half way. Let them grow again up to your desired size, but at least 12 inches or more, and cut them in half again.
What this does is give energy to the onion bulb and roots resulting in much bigger fruit. + you get the green onions which are in many ways just as good as the bulb.