Tamatar Raita 4 Green New Mexico Green Chiles -- roasted and chopped 1 Teaspoon Black Mustard Seeds 1/2 Teaspoon Cumin Seed 1 Cup Plain Yogurt 1/4 Cup Sour Cream 1 Small Onion -- finely chopped 1/4 Teaspoon White Pepper 1 Tablespoon Cilantro -- chopped 2 Medium Tomato -- chopped Toast seeds on hot griddle until they crackle and pop. combine all ingredients in large bowl. let sit for 1 hour or more to blend flavors.