If you ask 5 different people what ingredients are required to make som tom, you will get 5 different lists. Everyone seems to have their own version. Mom likes som tom Lao, which is more on the sour side. She uses a type of fermented fish juice in addition to fish sauce, sour cherry tomatoes, and limes. I prefer som tom Thai, which is a little sweeter while still having a bit of sourness (and usually no fermented fish juice). BTW the som tom served at Thai restaurants in the US resembles som tom Thai.
The bare minimum you’ll need are green papaya, fresh lime juice, fish sauce, tomatoes, garlic, Thai chilies and a pinch of sugar. Tasty additions include any (or all) of the following: roasted unsalted peanuts, good quality dried shrimp, tamarind puree and snake beans (Chinese long green beans) cut into 1 inch pieces.
Green papaya is not like the Mexican papaya you will find at your local Safeway. It is firm and the flesh is white. When it starts to ripen, the flesh will get a little yellowish, but it will never taste sweet or get soft. Avoid buying the pre-shredded papaya, since you don’t know how long it’s been sitting there. It could be limp or mushy. One medium-sized papaya will give me at least 2 portions (each portion is enough for 2-3 adults). I usually cut it in half and wrap one half up tightly with plastic wrap. It should easily keep for 4 or more days in the fridge (so you could make som tom twice in one week!). To shred the papaya, I recommend this. It gives the perfect thickness and length every time. It cost me like $4 at my Thai market, but you can order it here (but you'll pay a premium).
I feel I should say something about the dried shrimp. I love it in my som tom (and other foods), but I rarely use it because the quality of the shrimp I can get here in the States sucks. The stuff mom brings from Thailand is so much better; there really is no comparison. Somehow she always seems to have an abundance, probably because she visits home about once a year and her friends are always bringing some back for her. It’s really not necessary for som tom, so if you can’t find any you like, no problem.
To make a proper som tom, you should use this. The entire set up shouldn’t cost more than $10-$15. The sole purpose of this mortar is to make som tom (although I do use it occasionally for pounding other Thai spices-but don’t tell mom. She wouldn’t approve). Over time it will become well seasoned. To keep it in good shape, rinse it with really hot water after use and dry it immediately. Same thing with the pestle.
I like to start by making the “dressing” first. I normally don’t measure it out, but I made an effort this time.
- 3 tbs tamarind puree (explained in this post)
- ½ tbs sugar
- juice from approximately half a lime
- 1 tbs fish sauce
If you are using dried shrimp, soak them for 5 minutes then give them a good rinse and drain.
In your mortar, pound 1-2 cloves garlic and 2 chilies (for mild use one chili that is seeded; for hot use 3 or more) until they are nicely mashed. Add the dried shrimp and snake beans (about 1/4 to 1/2 cup in 1 inch pieces) if using. Pound a little more and use a spoon to scrape the food off the bottom and sides of the mortar. Add the tomatoes (about 1 large or 8-10 cherry tomatoes) then the shredded papaya on top. Drizzle about 1/3 to ½ of the dressing on top. Pound gently a few times, then scrape, making sure to turn the stuff at the bottom. You’re not trying to obliterate the food, just soften it to allow the flavors to blend together. Continue in this way until the salad is well mixed. Taste and add more dressing or any of the single ingredients until you get the flavor you want. Sprinkle with roasted peanuts, if desired. Serve immediately. This is not a dish you want sitting around for too long, or the lime juices will pickle the papaya.
Som tom is perfect with sticky rice. Or wrap in cabbage or lettuce leaves. It’s also a great side dish to grilled meats like this.