Microwave Polenta

In deep 2 1/2-quart microwave-safe bowl or casserole, stir boiling water, milk, cornmeal, and salt. Cover with waxed paper and cook in microwave on High 5 minutes. Remove bowl from microwave and whisk mixture vigorously until smooth (mixture will be lumpy at first). Microwave, covered, on High 2 to 3 minutes longer or until thickened, whisking once after cooking is over. Makes 3 cups.