This is the way. I'd probably do four controls though.
Higher end CNC-esque jog dial for control. ex. http://pico-systems.com/images/pendant.jpg (10th of a second increments maybe. Sometimes putting in 3 seconds to warm a tablespoon of syrup is useful or 24 seconds to warm your teacup).
Momentary switch to start.
Seven segment display array for time setting and countdown.
Sound cue to let you know when countdown has finished. Disabled via a prominent toggle switch. I'd say annunciator to keep with the industrial terminology but...