An Orange and Ginger Chicken recipe that I recently tried called for “dry mustard,” which I didn’t have on hand and couldn’t easily locate at my neighborhood grocery store.

But I knew I had black mustard seeds in my kitchen cupboard, which I’ve used for countless Indian curries. Hmm. I was pretty sure that dry mustard is usually yellow in color. How on earth could black mustard seeds turn into something yellow?

Well, who knew! As I started to pound the black mustard seeds in my mortar and pestle, this is what happened (see above photo). Turns out they’re black on the outside, but a sunny yellow in the inside. I’m sure that’s a metaphor for something. Regardless, my problem was solved.

If you have a dining companion who’s a perfectionist, as I do, here’s a good task for that person: Make him slice the kaffir lime leaves!

I’ve written before about how to shred kaffir lime leaves, a technique that I’ve recently learned is called “chiffonade.” I don’t have the skill, patience or — truth be told — desire to know how to do such an exasperating thing. Which is why I am glad I do know someone who does. Here’s a photo of his handiwork, above.

I’ve often complained that it’s tough to make curry, even in New York, because it’s difficult to find fresh ingredients — things like lemongrass, galangal and kaffir lime leaves — for which there are no substitutes. One of my reliable haunts is Kalustyan’s, at 28th and Lex, which is particularly noted for its Indian spices, dried chilis and other fixings (like frozen naan).

The other is Bangkok Center Grocery on Mosco Street in Chinatown, where I routinely make pilgrimages. Especially as I’ve begun focusing on Thai curries, this place is a godsend. It’s small and a bit cramped, but amazingly well-stocked with pretty much anything you could possibly need for a Thai curry. One of my first trips there, I picked up all the ingredients for a green curry paste, and brought it up to the counter — to my amazement, the young Thai guy working there took one look and said, “I see you’re making a green curry paste.” This is a place where curry-a-holics, like myself, are welcome.

On a recent trip, I found the usual assortment of things I have trouble locating elsewhere, from cans of coconut cream (cream, not milk) to fresh bunches of holy basil. And a highlight: they had just gotten a shipment in of kaffir lime leaves (pictured left). That’s  something like the holy grail, for this blogger.

The store seems to have a new website, with links to suggested recipes. This one for Penang Curry with Chicken looks delicious. I may need to head down to Bangkok Center Grocery to pick up some ingredients….

There is nothing so wondrous as a kaffir lime leaf.

These deep, glossy, emerald-green leaves impart a heavenly aroma: it’s a scent of rich citrus, as if already infused with coconut and spice. The addition of kaffir lime leaves can make or break an Asian dish, especially Thai cuisine, and the zest of kaffir limes (which look like odd, nubbly versions of regular limes) is an integral part of many curry pastes.

Is there a substitute for kaffir lime leaf? Maybe, but I can’t imagine anything that would add the same delicious impact.

There are numerous ways to add kaffir lime leaf to a dish – you can bruise it, you can tear it, you can add it whole. Or, you can slice it finely. Here’s how I learned to do that in Bangkok.

Take the leaves (most kaffir limes leaves are in double sections) and fold them over so you can grasp the spine, as pictured above; remove the spine. Stack the leaves on top of one another, shiny side up. Roll into a tiny scroll, and then slice finely.

Add a number of kaffir lime leaves, sliced in this manner, to a dish, or use as a garnish. I was surprised in Thai cooking class how many kaffir lime leaves we used — perhaps more than six to a dish. So in doubt, add a few more … and enjoy the result.

As names go, lemongrass is pretty on the money. It’s a grassy, reedy plant with the aromatic scent of fresh-cut lemons. It adds a delicious citrus-y note to dishes — and it’s a must in most Thai curry pastes (both green and red).

I was a bit intimidated the first time I bought lemongrass — how on earth does one add this foot-long stalk to a recipe? Turns out, it’s much easier than I thought. In Thai Cooking School, my instructor explained that you slice diagonally, starting from the bulb, until you no longer see any more purple.  You wind up using only about one-third of the stalk — but at least you’re using the most tender, lemon-y parts.

You can certainly buy an already-made curry powder. But if you’d like to experiment with your spices, it’s simple. Here’s my personal favorite version of homemade curry powder. This makes about a teaspoon – adjust if you need more:

pinch fennel seeds
1/4 tsp ground coriander
1/4 tsp ground cumin
1/4 tsp turmeric
1/4 tsp chili powder
black pepper

When you include this in recipes, feel free to add some dried chili peppers to kick up the heat.

Most of the spices in the above photo came from Queens, N.Y. — an excellent place to shop for curry-makings. The best stores, of course, are in Jackson Heights, but even little corner shops in other neighborhoods will be well-stocked. That big container of coriander, for instance, came from a little store under the elevated tracks near Sunnyside.

A reader named Gail recently posed this question about the Halibut in Red Curry Coconut Sauce recipe — how do you bruise the kaffir lime leaves?

Excellent question Gail! I watched my Thai cooking instructor do this, when I took cooking classes in Bangkok…you simply take the pestle and bang (lightly) the kaffir lime leaves. It’s fun. In the past I’ve ripped the leaves, to get the flavor out faster, but I think this is a better option.

Coriander root –  which is just what it sounds like, the long stringy roots of cilantro a.k.a. coriander — can be exceptionally hard to find in U.S. markets. For some reason, grocers chop it off (perhaps because the green leaves look nicer) which can be frustrating if you need it to make a curry paste or any other type of Asian dish. I think I’ve gone to six supermarkets in one night, searching for coriander with its roots still intact. In a pinch, if you can’t find coriander root, you can take the green stems and double them up. But it’s not as fun.

Many thanks to Citarella grocery store in Manhattan for keeping the roots on (see picture) – where they belong!