We heat the four tiny bars for ~3 minutes. They may stay white for a while but when they go brown, it burns super quick! So, for that 2-3.5 minutes, you SHOULD be looking at the kit kat very carefully or you may have some burn kit kat! Or worst, fire!
note: We put the kit kat in freezer over night.a
note2: We burned our first batch as I cooked it for may be 30 secs more. They were still tasty but not quite Facebook photo quality!
note 3: We bought our bag in Tokyo Japan for 200 Yen! But it is highway robbery price of over C$5 in Calgary at T&T supermarket, not worth that price if you ask me!