Answer: That's a good question, and one that we are asked frequently. The short answer is, it depends on the recipe. If it calls for a weight (not a cup measurement), you should weigh the ingredient. However, when one of our recipes calls for a weight, we also give you an approximate cup measurement. For chocolate chips, we usually specify both.
A note on measuring cups: There are two main types -- liquid and dry. The liquid ones are usually glass or plastic with a handle. They allow you to pour a liquid into the cup and bring it even with a measurement line without spilling. Dry measuring cups (like the one shown above) hold the exact amount and are designed to be leveled off with a flat edge. Trying to measure liquids in a dry measuring cup usually results in spilling.
An ounce for an ounce? Not exactly: The ounce measurement can be confusing. The liquid measuring cups indicate that 1 cup = 8 ounces. But it really means 1 cup of liquid = 8 ounces. Dry ingredients, however, vary greatly in weight. For example, 1 cup of all-purpose flour weighs only 4.5 ounces -- not 8 ounces.
How to measure flour: This is especially important when baking, as improper measuring can throw off a recipe. For best results, stir the flour and lightly spoon it into the dry measuring cup. Do not tap or pack the flour into the cup; doing so would add more flour than the recipes calls for. Level the flour by taking a flat edge and pushing it across the top of the measuring cup to remove the excess.