How to measure ingredients
A dash of this, a dollop of that ... some recipes are easy to modify according to what ingredients you have on hand and your individual preferences. Others, however, particularly for baking, require precise measurements. Here's how to make sure you always measure the correct amount.
For liquid ingredients
Use wet measuring cups. A wet measuring cup has the line a little below the top of the cup, so you can avoid spillage.
Tapping a wet measuring cup to settle a dry ingredient to the desired line will cause some fine ingredients, such as flour or sugar, to compact. This can ruin fragile recipes. A dry measuring cup filled to the top with a liquid will yield a roughly correct measurement, though pouring it may be messier without a spout.
Several online resources, such as this one, provide measurement conversions for commonly used dry and wet ingredients.
For dry ingredients (such as flour)
Spoon the ingredient into a measuring cup until it overflows, filling the cup until it domes up over the top. Don't scoop with the cup and shake off the excess, because this will cause the ingredient to become slightly packed and you'll end up with more than the recipe calls for. (For heavier ingredients, such as granulated sugar, go ahead and scoop.)
Then, level the cup off by running the flat edge of a knife over the top of the measuring cup. This will ensure that you've measured the exact amount the recipe calls for.
To use measuring spoons
To measure light and fluffy ingredients, put the ingredient into the measuring spoon with another spoon or scoop, until it domes up over the top of the measuring spoon. Then run the flat edge of a knife over the top of the measuring spoon to level it off.
For salt, granulated sugar, or other heavy ingredients, it's okay to dip your measuring spoon, scooping out enough so the spoon is overflowing.
Sources: Real Simple and Chow.com