The onions should practically disintegrate into the sauce. Adding the oil at
the end lends a bit of extra richness; traditionally more lard or oil was added
than prescribed here to also give an appetizing sheen to the shrimp.
1 1/2 pounds (31-40 count) medium shrimp, peeled and deveined
Place the shrimp, salt, fish sauce and Caramel Sauce into a shallow saucepan.
Bring to a vigorous simmer over high heat.
Add the yellow onion and pepper,
stirring to evenly distribute. Continue cooking over high heat, occasionally
turning the shrimp so that they're well coated with sauce. They'll curl
up and release their juices to combine with the other ingredients and concentrate
into a dark sauce. Add a little water if things get too dry.
The shrimp are done when they've taken on an orange-brown color and
have a pleasant sweet chewiness, about 8 to 10 minutes after you've added
the onion and pepper. There will be a few tablespoons of sauce in the pan.
Remove from the heat, add the oil and stir to coat the shrimp.
Scatter the green onion on top and serve with lots of steamed rice.