A cake tester is a kitchen tool which is designed specifically for use in baking. It is meant to be used to test the doneness of cakes, a crucial step in the baking process which can make or break a cake success. Many kitchen supply stores sell cake testers, and while they are not vitally necessary for all cooks, they can certainly be useful.

The design of a cake tester is very simple. A rounded ring or paddle handle holds a long, thin wire which is meant to be insterted into the cake as a probe. If the cake tester comes out clean, the cake is done and it should be pulled out to cool. If crumbs are left behind on the cake tester, the cake is not quite finished, and it should be allowed to bake a little longer. There are some exceptions to this rule; banana bread, for example, tastes best when there is still some residue on the cake tester.

All cakes should be tested for doneness before they are pulled out of the oven. Many things can impact the cooking time for a cake, starting with what kind of pan is used, how hot the oven actually is, and small variations in the ingredients. A recipe's published cooking time is often a close guide, but it is rarely perfect. For this reason, almost all recipes encourage cooks to test the doneness of cakes with a cake tester or a similar tool, specifying if residue should be left behind on the cake tester or not.

There are numerous substitutes for a cake tester which can often be found around the kitchen. Many cooks use toothpicks, which have the disadvantages of being non-reusable and sometimes too short. Other long, thin utensils like skewers, knives, and straightened out paper clips can be used as a cake tester as well. Some of these tools are also more likely to leave holes in the finished product, so caution is necessary when using them.

As a general rule, a cake tester should be made from metal, so that it is washable and reusable. Many cake testers are designed to be dishwasher safe, although in practice this sometimes means that the cake tester slips out of the silverware rack and settles in the bottom of the dishwasher. Hand washing may be easier in this particular instance. It is also a good idea to look for a cake tester with a big, bright handle so that it can be easily found in a kitchen tool drawer.