Pierce potatoes with a fork, and arrange in a circle on paper towels in microwave oven. Microwave at HIGH 10 minutes or until tender, rearranging potatoes after 5 minutes. Wrap in a towel; let stand 5 minutes. Peel and mash potatoes. Combine with milk and remaining ingredients.
Place in a 1-quart casserole; cover and microwave on MEDIUM for 7 minutes or until thoroughly heated.