The first kitchen chore I was ever tasked with was picking cilantro leaves. It happened one Sunday morning, as my father was making aloo paratha, the flaky Indian flatbread that's stuffed with spiced mashed potatoes. I was loitering impatiently at the edge of the kitchen, and he asked me to go through a bunch of cilantro for the filling. I can still remember how strongly he emphasized the importance of making sure each leaf was stem-free—he claimed that even a little bit of stem could ruin the paratha experience.
Of course, that isn't true—cilantro's stems are perfectly easy to eat (my father can be a bit picky). And yet, for decades, I continued to painstakingly go over bunches of cilantro in my home kitchen, plucking each leaf free; after washing and spinning dry all the leaves, I'd throw the pile of stems into the trash.
Nowadays, though, I know better. First off, I follow Kenji's carefully researched guidelines for storing fresh herbs like cilantro, parsley, mint, and basil. I use the tender stems in salads or sandwiches, and, on occasion, I finely chop them and add them to nuoc cham. And when I'm making other Southeast Asian dishes, like Thai-Style Grilled Chicken, I follow Kenji's hack of substituting those flavorful cilantro stems for cilantro root, which can be exceedingly difficult to find.
Long story short, while we often use only the tender leaves of herbs in finished dishes, the stems still have plenty to offer. The next time you're getting ready to toss a bundle, consider saving them for bouquet garni, the seasoning bundle that can flavor chicken stock and stews like this Provençal ratatouille.
Toss a few extra stems into the pan to add complexity to your next butter-basted steak. Want to enjoy a Béarnaise with that steak? Grab some chervil and tarragon stems. Similarly, basil stems make a great addition to tomato sauces, of both the quick-cooked and slow-cooked varieties.
Herb stems are also far hardier than their leaves, which means that they stand up to freezing better. So if you're going to chop up herbs and freeze them in oil, or if you're planning on drying your herbs in the microwave, consider tossing the unused stems in a freezer bag along with vegetable scraps; they could come in handy for your next quick vegetable stock.