How to measure butter using cups as a unit of measurement

This might be a bit of a silly problem but I'm really confused. The recipe I'm using ( https://www.geekychef.com/2016/02/toriels-butterscotch-cinnamon-pie.html ) needs 1/2 cup of butter and I'm kinda confused about how to measure that. Every recipe I've used had grams as a unit for butter (I've only ever seen cups used for melted butter).