Spicy lentil soup is a soup dish made using lentils and a variety of spices. The ingredients in each individual recipe differ, but anything which contains lentils and spices that is served as a soup can be classed as a spicy lentil soup. Generally, spicy lentil soup will include red lentils, onions, carrots, vegetable stock, ginger, and some spices such as cumin and chili flakes. Variations include different spices, additional main ingredients such as garlic, and some add coriander just before serving. Most ingredients are shallow-fried, and then the lentils and stock are added for the final simmering process.
Different ingredients are used by different chefs, but some core ingredients are present in almost all recipes for spicy lentil soup. Most recipes use red lentils and vegetable stock, which make up the bulk of the dish. These are added to cooked onions and carrots, which are often cooked in spices. The most commonly used spices are cumin and chili flakes, which add some flavor and spiciness to the dish. Coriander is the most common herb added to the soup.
The general process of making spicy lentil soup is the same regardless of the specific ingredients used. Chefs add oil to a hot pan and cook the onions in it, sometimes alongside or after the cumin and chili flakes. This forms a base flavor, with the aromas released by the cumin seeds and the sweated onion infusing into the oil. Vegetables, generally just carrots, are then added to the pan and cooked for a short period of time. The final ingredients to be added are the lentils, the stock, and, after a 15-minute simmering period, any additional herbs.
Variations on the standard recipe are common, and different spices are one of the most common differences. The main flavor of the spicy lentil soup comes from the spices which are added to it. Aside from cumin seeds and chili flakes, commonly used spices include turmeric, garam masala, and cayenne pepper. Herbs beside coriander are also common in different recipes, with bay leaves and basil being two examples.
Some chefs also add more ingredients to the dish, including garlic, peppers, and potatoes. Garlic is generally added to the spicy lentil soup at the same time the onion is, to allow the garlic to release its flavors before the lentils and stock are added. Other ingredients like peppers and potatoes are usually added at the same time as the carrots. Many chefs also like to top the soup with yogurt and serve it with naan bread.