Photo: Paige Green © 2014
Shrimp cooked in caramel sauce (tom kho) is among my favorite Viet comfort foods. I typically eat it with rice, but one day I slid leftovers into a roll for a surprisingly fantastic banh mi. Traditionally, tom kho is prepared with shell-on shrimp and caramel sauce, which is, basically, nearly burnt sugar. Most cooks lack a jar of caramel sauce in their pantry; here's a method for individual batches. Vigorously cooking shrimp for a long time seems counterintuitive, but it yields shrimp that seem almost candied.
- 1 1/2 pounds (675 g) medium shell-on shrimp (35/40 count)
- 1 tablespoon fish sauce
- 1/2 medium yellow onion or 1 large shallot, thinly sliced
- 3 tablespoons sugar
- 2 or 3 drops distilled white vinegar or lemon or lime juice (optional, for preventing crystallization)
- Generous 1 tablespoon canola oil
- 1/4 to 1/2 teaspoon black pepper
- 1 green onion, green part only, cut into thin rings
Peel and devein the shrimp; put them in a colander and toss with 1/2 teaspoon of salt. Rinse, drain well, then put into a bowl. Add a big pinch of salt, then the fish sauce and onion. Set near the stove.
Select a heavy medium skillet or a shallow medium saucepan with a light-colored interior (to easily monitor the caramelization process). Put the sugar, 1 tablespoon of water, and the vinegar in the pan. Heat over medium heat, stirring with a metal spoon or rubber spatula, until relatively smooth and clear, about 1 minute. Stop stirring and let the sugar cook.
When the sugar is champagne yellow, after about 4 minutes, pay attention. Swirl the pan for about 1 minute to coax the sugar to a light tea color; swirl a bit longer for a darker shade and a slight bittersweetness. Faint smoke may rise toward the end.
Turn off the heat and let the sugar continue caramelizing on the hot burner until it is dark amber, about 3 minutes. Add a splash of water to the pan, then reheat over medium-high heat, stirring to loosen the caramelized sugar from the bottom. Add the shrimp and onion mixture, and raise the heat to high, so it is vigorously bubbling. Cook for 13 to 15 minutes, stirring frequently, until the shrimp are orange-brown and 1 to 2 tablespoons of slightly syrupy liquid remains.
Add the oil and cook for another minute; there will be little liquid left at the end. Off heat, stir in the black pepper and green onion. Taste and add a pinch of salt if you like. Enjoy warm or at room temperature in sandwiches.
Note: In a shrimp in caramel sauce banh mi, use the snow pea or daikon and carrot pickle, cucumber, cilantro, and chile. Any of the mayonnaises will work. The shrimp flavor is bold, so you may not need Maggi.