This is a common garnish used in Vietnamese dishes. It's added right at the end to add a richness and sometimes slight crunch if the dish isn't liquidy or saucy. Many Viet people use it like bacon-bits and fry up dehydrated onion or pre-dried shallot. The best is made fresh.
Crispy Caramelized Shallot
Makes about 1/3 cup
1/2 cup thinly sliced shallot (1 very large or 2-3 small shallots)
3 tablespoons neutral-flavored oil (canola, corn, or vegetable)
1. To help the shallot crisp up, first remove some excess moisture. Do your best to use your fingers to separate the slices into individual layers, depositing them on a paper towel. Gather up the paper towel and gently blot away the moisture. Set near the stove.
2. Heat the oil in a 10-inch skillet over medium-low heat. Add the shallot and gently fry, stirring occasionally to ensure even cooking. After 5 to 6 minutes, when the shallot is fragrant and turning light golden, watch the skillet carefully, moving it frequently by stirring or swirling the skillet. During frying, the shallot will soften into a mass and then stiffen as it caramelizes and crisps. When most of the shallot slices are rich golden brown, turn off the heat. (Total cooking time is about 10 minutes.) Using a slotted spoon, transfer to a paper towel-lined plate, leaving as much oil behind in the skillet as possible; discard or use the fragrant oil for other uses. Spread the shallot out in one layer. When they've cooled, crisped, and slightly darkened, transfer them to a small bowl or plate.
Kept uncovered at room temperature, the shallots retain their crispiness for a good 8 hours. Even if they no longer rustle when you shake them, they're still tasty.
Crispy Caramelized Shallot is from Into the Vietnamese Kitchen: Treasured Foodways, Modern Flavors (Ten Speed Press, 2006)