Toothpicks are the gold-standard of cake testing. Most, if not all, recipes call for them and even though there are other ways to test for doneness (for instance, lightly pressing the top of a muffin/cake to see if it springs back into place), checking to see if a toothpick inserted into the center of a baked good comes out clean is consistently reliable. But many cookware and kitchen stores stock actual “cake testers” – are these better than old, reliable toothpicks?
The answer really is no. Performance is similar, and it’s unlikely that you’re going to have any real problems from using a metal cake tester, but the reason why the idea of toothpicks as cake testers has been around so long is that it works extremely well. The slightly textured wood of the toothpick makes it easier for the toothpick to “grip” little crumbs, giving you a fairly accurate idea of doneness, while a metal cake tester can be too smooth to do so. Arguments for cake testers say that they’re cleaner because you can wash them. Toothpicks are disposable and are only used once, so that doesn’t hold up. They also say that they’re longer and work with a wider variety of baked goods – which is true, but you can just as easily use a bamboo or other wooden skewer for a deep cake in place of a toothpick.
It comes down to personal preference, but you’re not going to get drastically better outcomes with a cake tester. I’ll stick with toothpicks, myself.