I am going to post a number of parts to this post over the next weeks, since writing everything at once wouldn't work. The trips were in January and April.
My first subject is som tam or tam mak hoong or tam bak hoong. In two trips to Thailand this year, I had som tam a number of times, always with pla ra (pronounced paa laa by most in Issan - my wife is from Issan). The best I had was at a som tom maker's roadside table along the road from Ubon Ratchathani to Amnat Charoen about 6-8 km from the intersection of 231 and 212.
My brother-in-law had brought 830 kg of papaya (malagor pronounced malagaw) from a farm in Loei province, and had sold 500 kg in Roi Et the day before. He was trying to sell the last 280 Kg in 10 kg bags, and the som tom maker bought 3 bags at 75 - 80 baht / bag. He took one of the papayas in the back and quickly skinned it to check the quality.
Since he had got it ready for use, I decided to buy an order of som tam from him (15 baht). He made quick work of julienning the papaya. I requested it with paa laa, and only one "super hot" ("super hot" seems to have replaced phrik khi nu, pronounced pik kee nu in Issan, almost everywhere) pepper and only a very small amount of sugar (my wife likes som tom very sour, I like it somewhat sweeter) with the ubiquitous black crab.
When it was ready, everyone (there was 6 of us) had some, but I fortunately got a lot of it since he had used two handfuls of papaya shreds. The crunchiness and moisture of the papaya was exquisite. I suspect that it was so good because of the freshness of the papaya and that it was somewhat chilled.
I ordered two orders of som tom from him several days later and took it back to where we were staying, but even though it was good, it wasn't quite as good as the first time. In those, I got a total of 4 peppers, spicier, but still not at a level that I am OK with. After buying the last 2 orders, the som tam maker ordered the two bags of papaya my brother -in-law had left.
I had som tam that my 8 year old niece made several times, that was quite good, but also on the sour side. I had some som tam from a restaurant across the street from Bangkok Nurses Hospital and on my several day trip in April, I had som tam from a street cart vendor behind the TukCom building in south Pattaya. Both times, the som tam was excellent but didn't have the extra provided by the farm fresh papayas.
For those that haven't tried dishes with paa laa, it's blending in food isn't what one might think. It has a mild flavor that accents the other ingredients, instead of overwhelming them. It is also slightly sweet when combined. It is pickled, a process that is used to preserve many foods.