The most common type of cookie seems to be the drop cookie. Chocolate chip, oatmeal and anything else that must be scooped and dropped (hence the name) onto a baking sheet without any shaping or rolling falls into this category and, despite how prevalent they are, there is a lot of debate over how exactly you’re supposed to drop the chunks of cookie dough onto your baking sheet. How big should the cookies be? How do you get them to all turn out to be the same size?
Most recipes call for dough to be dropped in “heaping teaspoonfuls” or “rounded tablespoonfuls” and I have to admit that I am no exception here (although I do try to give a more concrete estimate of the size by saying things like “1-inch in diameter” when I can). These measures are based on actual spoonful amounts, not on measuring spoons. Think of your silverware drawer. Odds are that you have two sizes of spoons in there: smalls are teaspoons and larges are tablespoons. They don’t correspond exactly to the size of a measuring spoon, but tableware is where the measurement originated – and where the measurement for cookie dough scoop sizes still lies. A rounded or heaping tablespoonful is going to be about 2 measured tablespoons. A rounded or heaping teaspoonful is going to be about 1 measured tablespoon.
I shape my drop cookie dough using these spoons to pick up a smallish amount of dough then using a round butter knife to push the dough onto the baking sheet. This gives me a round piece of dough (a proto-cookie, if you will) and keeps my fingers clean. Once I have one, I simply eyeball the rest to match. As long as you make all your cookies about the same size – teaspoon or tablespoon – there really is no “wrong” option. Just be sure to keep an eye on the baking time while your cookies are in the oven, because if your cookies are smaller than the recipe writer’s were, they will bake a bit more quickly. If they are larger, they could take a minute or two longer.
Now, if you don’t feel comfortable “eyeballing” your dough like I do – although I assure you that the longer you do it, the more consistent your cookies will get – you can invest in a cookie scoop to do the measuring for you. Cookie scoops come in different sizes to take the guesswork out of the “rounded tablespoon” approximations and they work just like mini ice cream scoops, complete with small levers that push the dough out of the scoop and onto your baking sheet in a perfectly portioned ball. The downside is that dough will inevitably stick to them no matter how good the lever mechanism is (happens with ice cream scoops, too), so you might have to dip them in warm water a few times while you work to keep them slippery.