Obtaining a Scorched Alaska (dish) is one of the main objectives in Part II. Flambe, the French-accented demon, wants it before he agrees to do you a favor. When you finally manage to acquire the dish, it would not be too scorched, so no point in trying it out at that point. When you figure a way to make it properly hot though (still, required to progress the story), you can force Guybrush to try it out. He will refuse at first, but keep on trying and, eventually, he will try this death-defying feat.