I used to watch my brassicas (kale and arugulas mostly) make flowers and feel doom in my heart... the end was near... poor me... no more kale or arugula soon...
But now I eat those flower buds and keep my kale patch happier and healthier longer. I also keep myself happier and healthy, too.
You've heard of rapini and broccoli raab, yes? Raab comes in the spring, from over-wintered brassica varieties. The raab is the flower buds that look like tiny broccoli heads -- hence the classic "broccoli raab" that grows from mustard greens (also in the brassica family) and not from a genuine broccoli plant. You can have kale raab, turnip raab, arugula raab, mustard raab, collard raab, and many traditional Asian greens that feature the flower bud. They're all good.
Fresh-picked raab is sweet. Before writing this post, I consulted every vegetable-loving cookbook in my large library, and all of them talked about how bitter raab can be and how necessary it is to cook it well.
Pardon me for disagreeing with famous chefs, but I suspect the issue with raab is that it is best fresh from the garden -- like corn. Perhaps the longer it takes to get from farm to kitchen, the more in need of cooking it is. I'm delighted to eat it raw because raab is amazingly tender and sweet.
Think: the little kale, turnip, mustard, and arugula plants have spent early spring growing leaves and soaking in the sun, and they're ready to attract bees and other beneficial insects. They put all their sweetest, freshest energy into those tender flower stalks and buds. They're "springy," porous, tender, sweet, bright. So little effort is needed to chew them because they're perfect little flowers ready to bloom.
You can do as I do and just stand in your garden, picking and eating kale flower buds like a cow, or you could pick them and run inside to your kitchen that's ready with a warm skillet and a cutting board full of chopped garlic. Turn the skillet on high, throw in the raab and some garlic, a little salt, lots of pepper, a splash of lemon juice or favorite vinegar, and then spoon the greens onto plates or bowls. 5 minutes from garden to plate.
You want your own raab. You do. Try growing your own kale!
We live in Oregon (zone 8 and had a lot of snow last year and some bitter cold), and I plant kale and arugula seeds in the fall and then leave them. They start to come up in late fall and then die down when the cold gets bad. Then they don't come up again until late February. Then they get frozen and disintegrated by the next round of snow. Then, in March when the light really does seem to last longer each day, they start growing, and you need to do nothing to these plants but eat their tender leaves frequently and sing them songs. (E sings the ABC song to them pretty regularly.)