Go to a well-stocked Indian market, and you'll find an overwhelming variety of dried lentils: different colors, some with skins on, some with skins off. But in most mainstream groceries, the varieties are limited to three or four.
Because the cooking time can vary by age and variety, follow the directions on the package for basic cooking. A good rule of thumb is to rinse the lentils under cold running water, then combine 1 cup lentils with 3 cups water and a pinch of salt, bring to a boil, reduce to a very gentle simmer, cover, and cook for the recommended amount of time.
Here's what the most common varieties are best used for, and how long they typically take to cook.
Red, orange or yellow split lentils: Commonly used for Indian dal, these break up during cooking. Best for mashes, soups and stews.
Cooking time: 15-25 minutes or more, depending on how soft and disintegrated you want them.
Black beluga lentils: Small, shiny and black, they resemble caviar and maintain their shape and firm texture when cooked. Best for salads or appetizers, such as on blini.
Cooking time: 20 to 25 minutes.
French du Puy lentils: These small, blue-green-spotted lentils keep their shape when cooked and have a particularly creamy texture. Best for cold or warm salads.
Cooking time: 25-30 minutes.
Brown or green lentils: Larger varieties, these can get mushy when overcooked but otherwise keep their shape. Good for sauces or for playing the part of meat in taco fillings, sloppy Joes and more.
Cooking time: 30-40 minutes.