Measuring butter - Is it melted or solid

The butter can be either melted or solid . . . . but you are heating it in a pan anyway to make the sauce, so you needn't bother to melt it beforehand.

As for measuring, some sticks of butter have markers on the side of the wrapper showing where to cut. If you don't have butter that is marked that way, then weighing is the best way to go. The two tablespoons of butter would be one ounce or 28.4 grams on the scale. ;o)