Aphids are fairly easy to get rid of, with a little persistance. They reproduce very quickly in warm weather and may even be born pregnant. (neat trick) Since these are on an edible plant, you won’t want to use a toxic insecticide. Here’s what I’d do. Squirt dishwashing on your hands and add the tiniest bit of water to loosen up the suds a little. Rub the entire plants, leaves (tops and undersides) and stems. If it grosses you out to think about touching the aphids, you can wear latex gloves. Let the plant sit there, all soapy, for 15 minutes, then rinse it off, thoroughly. Repeat this every 3-5 days for a total of 4-5 times and you should get them all. If they persist, continue the process or use a pyrethrin spray labeled for vegetables. Good luck!