Add the cilantro, mint, red onion, garlic, ginger, and salt, and pepper, to taste, to a food processor or blender. Puree on high until smooth. With the processor running, add about 1/4 cup water, and blend until the mixture is the consistency of a thick paste, a.k.a. "masala". Set aside.
In a large pot or deep skillet heat the olive oil over medium heat until shimmering. Add the shallot and cook, stirring often, until golden brown.
Add the spices and cook for 30 seconds. Pour the masala mixture into skillet and cook, stirring often until it deepens in color and aroma. You'll know it's ready when it looks shiny, little droplets of oil will appear on the surface, and the masala will hold together as a cohesive mass.
Add the chicken, coating every piece in the masala and stirring often. Continue to cook for 5 minutes, so that the masala really adheres to the chicken. Add about 1 1/2 cups water, just enough to cover the chicken, and the vinegar. Bring to a boil, and then reduce the heat and simmer, uncovered, until the chicken is tender and sauce has thickened slightly, about 20 to 25 minutes.
Remove the pan from heat and stir in the yogurt. Taste and adjust seasonings, if needed. Transfer the mixture to a serving dish and serve over rice or with warm naan bread.
Recipe courtesy of Aarti Sequeira