Pour milk into a heavy 4-quart saucepan. Bring to a boil over medium-high heat, stirring occasionally. Reduce heat to medium and stir in buttermilk. When the curds form a mass (you'll see a clear, pale-yellow whey surrounding the curds), remove pan from heat, Let stand, partially covered, for 10 minutes. Line a colander with a double layer of dampened cheesecloth. Set the colander in the sink or in a bowl if you wish to save the whey (see note). Gently pour the curds and whey into the cheesecloth. Gather together the corners of the cloth, give one or two twists, and tie with a kitchen twine. Hang the cheesecloth bag over the faucet and let the cheese drain for 1 hour, or until it is as thick as yogurt (this is channa). If the weather is warm, leave the cheesecloth bag in the colander, set the colander on a plate to catch the drippings, and refrigerate until the cheese has thickened. Unwrap the channa and use immediately, or cover and store in the refrigerator for up to 4 days. Yields approximately 10 ounces. Note: Save the whey for making your next batch of paneer, use it for cooking lentils or pilafs, or add it to soups. Paneer cheese: Snugly wrap cheesecloth around the channa to form a "cake." Place on a cookie sheet, place another cookie sheet on top and add weights (for example, 2 or 3 large cans of tomatoes, 2 or 3 bricks, a large pitcher of water). Let the cheese sit for 2 to 4 hours. Use immediately, or cover and refrigerate for up to 5 days. Yields 8 ounces (1 cup). PER OUNCE (channa): 75 calories, 5 g protein, 0 g carbohydrate, 6 g fat (4 g saturated), cholesterol and sodium content is not available, 0 g fiber. PER OUNCE (paneer): 100 calories, 7 g protein, 2 g carbohydrate, 7 g fat (5 g saturated), cholesterol and sodium content is not available, 0 g fiber. From an article by Lax Hiremath in the San Francisco Chronicle, 9/1/93.