Change the way you cook an onion (and anything else cooked with it), and change the taste of your dish. That slow sautéing we do in the Tomato Soup with Basil Yogurt Cream recipe is a chameleon technique. It converts eye-stinging onions to a sweet, creamy foundation for that soup which, in turn, points up the natural rich sweetness of the tomatoes. Here's how the technique works:
Slow, covered cooking in a little fat, as with those soup onions, teases out juices and natural sugars, mellowing the onions down to sweet and lush. Figure 20 to 30 minutes in a covered pot over medium-low to low heat.
When you want your tomato sauce to taste extra sweet and tomatoey, this is the way to go. Use in any dish. With hot chile dishes, like Indian and Thai curries, slow-cooked onions temper the hot peppers.
If you increase the heat once the onions are soft and creamy, and brown them to rich gold (stirring often to keep them from sticking), you have caramelized onions that border on a robust jam.
Fast browning is the bold opposite of sweet and creamy. The fast brown makes onions taste bold and meat-like with little sweetness. Here you want medium-high to high heat until ingredients brown to deep gold, usually in 4 to 8 minutes depending upon your pot.
This story appears in Eating In with Lynne Rossetto Kasper, Issue 1, which is available as an e-book.