Is your oven calibrated to the correct temperature? This little pile of sugar can tell you.
Sugar's melting point is 366℉ . So if you place a half-tablespoon of sugar in an oven heated to 375℉, and the sugar does not melt; your oven runs cold. Likewise, if you put the sugar in a 350℉ oven, and it melts; your oven runs hot.
So to test for a too-hot oven, start well below the melting point. Like this:
1. Heat the oven to...350℉.
2. Add about 1/2 tablespoon of common table sugar to an oven-safe dish. (Or better yet, to avoid the perils of molten-sugar clean-up, pour the sugar onto aluminum foil).
3. Put the dish into the hot oven and set the timer for 15 minutes.
4. When time's up, check the sugar. If it melted, the oven runs hot. If it didn't melt, start again. Raise the heat to 360 degrees F. And start again with Step 2. And so on.
To test for a too-cold oven, heat the oven to 375℉. Then follow steps 2 and 3.
This time, if the sugar does NOT melt (but is just a little discolored), then you’re running cold.
So then, to recap. If you discover that the sugar melts when the temperature reaches, say, 360℉, you know that your oven is off by about 6℉. Or put another way, when the dial reads 360℉, you know the temperature inside the oven is actually 366℉.
And, of course, you can always gauge the temperature with an oven-safe thermometer. But where's the fun in that?