A tamper-resistant lid assembly for dispensing a premeasured amount of liquid from a beverage container and a method of providing a tamper-resistant lid assembly for use in dispensing a premeasured amount of liquid. The assembly includes a cup and a ring that are secured to one another using a snap-fit connection, as well as a lockable connection enabled by a selectively twistable rotation of the cup and the ring once the snap-fit connection is established.