Start by chopping up the Brussels sprouts. I cut them in halves but you can quarter them too, if that's what you prefer.
Blanch them in boiling water for a couple of minutes and then remove and add them to an ice bath.
Drain the excess water, pat dry and transfer them to a glass jar along with the spices.
Prepare a brine using equal parts apple cider vinegar and water along with the salt, and pour the hot brine into the jar.
Notes
Make sure the Brussels sprouts are completely clean and free from any dirt. This is especially if you're using homegrown sprouts.
It also helps if you remove the first outer layer of the sprouts. These tend to be more tough and hard than the rest of the veggie.
I kept the brine tangy and salty, but if you really love a balanced flavor, you can also add a tablespoon of sugar into the pickling liquid. I did that when I made my quick pickled shallots and pickled eggs and sausage.
Make sure there's enough of the pickling liquid aka brine to completely cover all the Brussels sprouts. This is crucial, as it helps prevent spoilage.
In addition to Brussels sprouts, you can also add other veggies like carrots, cauliflower, asparagus and onions to the mix, and turn it into a mix veggie pickle. I did the same when I made my Torshi Makhloot.
Allow the jar to rest overnight in the refrigerator for the sprouts to soften and soak up the flavors nicely, and then serve.