You may think of lentils as something to store in the back of your pantry until a day when you have lots of time to wait for them to cook. But lentils, especially the red variety (sold in natural foods stores), are surprisingly convenient. They require no pre-soaking and cook up quickly — red lentils in just 20 minutes and brown (or green) lentils in about 30 minutes. Here's how to use lentils in a warming curried red lentil soup.