One of my foodiest friends (and trust me, in my circle this is saying something) posted this on Facebook the other day. I’m guilty of a lot of these kitchen crimes, though some unwittingly so. If you spend any time at all on your cooking, these tips are worth a look.
8. You don’t know your oven’s quirks and idiosyncrasies.
Result: Food cooks too fast, too slow, or unevenly.
Ideally, every oven set to 350° would heat to 350°. But many ovens don't, including expensive ones, and some change their behavior as they age. Always use an oven thermometer. Next, be aware of hot spots. If you’ve produced cake layers with wavy rather than flat tops, hot spots are the problem.
SaBrina Bone, who tests in our kitchen, advises the “bread test:” Arrange bread slices to cover the middle oven rack. Bake at 350° for a few minutes, and see which slices get singed―their location marks your oven's hot spot(s). If you know you have a hot spot in, say, the back left corner, avoid putting pans in that location, or rotate accordingly.
via Cooking Tips and Cooking Questions Answered – Cooking Light.