BLEND milk gradually into pudding mix. Add butter and half of the peanut butter.

MICROWAVE on MEDIUM power for 2 minutes; blend well. Microwave on HIGH power until mixture starts to boil around the edge, about 1 minute. Stir well.

QUICKLY blend in icing sugar. Spread evenly in waxed paper lined loaf pan.

MELT remaining peanut butter in microwave on HIGH power for 20 seconds. Pour over fudge. Chill 1 hour.