How to Use Residual Heat in the Oven
Reheating an entire oven takes a significant amount of energy, and it can seem a little wasteful to use it to heat up a single food item (be it a party pizza or a small pork loin). But as anyone who has ever used an oven knows, ovens remain hot and toasted even after they are turned off, such a miracle of thermodynamics, so you can also put that heat to work.
For example, suppose you bought (or baked) a lovely baguette to eat for your oven-baked dinner, but all your butter is (unfortunately) cold and hard. Pour the butter into a rimmed dish, place the dish in a warm oven and let it soften while you set the table. (How quickly it softens will depend on how hot the thing is, so use common sense.) If your bread is a little stale, don’t worry; The residual heat can also be used to make a loaf of bread that is crispy for a day or two ( rinse it under water first if really stale).
If a long time has passed and most of the heat has already gone out of the oven, you can turn up the cheese course using the last drop of heat to bring the fancy cheese to room temperature. ( Cheese at room temperature is much tastier than cold cheese.) You can also throw bread dough in there and use it as a proofing drawer – but only after it has cooled down significantly; you want it warm – 75 to 95ºF, not hot.
I find an oven still warm in the morning is especially helpful. I often keep the bacon in the oven after turning it off to keep it hot, and toss in the toast in there to keep it, well, toasted until the eggs are done. (I always cook the eggs last, as they cook quickly and should be served hot.) If the oven wasn’t too high to start, you can even use it as a plate warmer. Nothing spoils a hot egg like a cold plate.