Measuring 2/3 cup with 1 cup is a common task in cooking and baking. It can be done using a variety of methods, depending on the accuracy required and the tools available.
One simple method is to use the 1 cup measure to scoop up the ingredient and then level it off with a straight edge, such as a knife or spatula. This will give you a fairly accurate measurement, but it is not as precise as using a scale. Another method is to use a measuring cup with a pour spout. Fill the measuring cup to the 1 cup mark and then slowly pour out the ingredient until it reaches the 2/3 cup mark. This method is more precise than using a straight edge, but it can be more difficult to control the flow of the ingredient.