Pressure Cooker Scalloped Potatoes and Ham

Serves 4 to 6.. Grease a 1 1/2-quart casserole dish or heatproof glass bowl. Cube ham. Heat milk in microwave safe measuring cup. Saute onion in butter until tender but not browned. Stir in flour, salt and pepper. Add hot milk all at once and whisk over medium heat until thickened and bubbly. Thinly slice potatoes. Place half of potatoes in prepared casserole dish. Top with cubed ham. Cover with half of sauce. Cover with remaining sliced potatoes and sauce. Cover top of casserole dish with aluminum foil. Fold a strip of aluminum foil to fit around bottom of, and up sides, of casserole dish. Place rack into pressure cooker. Pour 1 1/2 cups water into pressure cooker. Place casserole dish with foil handle surrounding bottom and sides of dish. Cover and set pressure cooker control at 15 lbs. and cook 18 to 20 minutes. Remember to adjust cooking time, according to elevation. Cool cooker normally for 5 minutes and then cool under faucet. Carefully remove dish from pressure cooker using foil handle.