From America's Test Kitchen Season 5: A Passage to India
As with many other dishes of Indian origin, mulligatawny soup is mildly spicy and richly flavored, with a number of spices in its lineup. We wanted an elegant, but potent, rendition of this classic soup, not the thin, raw-tasting version found in many restaurants.
Chicken broth proved to be the best base for this pureed vegetable-laden soup; beef broth was too strong and vegetable broth gave us an overly vegetal soup. For the spices, good-quality curry powder is a must, and a little cumin and cayenne pepper made for the perfect spice mix. Garlic, ginger, and coconut were a given—essentials in mulligatawny—but the best way to incorporate them wasn’t immediately clear. We ended up adopting a technique common in Indian cooking—we pureed the raw garlic and ginger with water so they could be mixed into the soup for fresh bites of garlic and ginger. The best source for true coconut flavor turned out to be shredded unsweetened coconut.
Finally, to give the finished soup the right amount of body, we made a roux with our aromatics and pureed the soup with a banana, which imparted a rich, sweet flavor to the dish (a potato worked fine, too). A dollop of yogurt and sprinkling of cilantro were the crowning touches on our richly spiced, velvety mulligatawny.
Serves 6 to 8
For freshness, puree some of the garlic and ginger with water in a blender, then leave this mixture in the blender while making the soup. The finished soup is pureed in the same blender, where it will pick up a hit of spicy raw garlic and ginger flavor.