Soften butter slightly for easier mixing by removing from refrigerator and letting stand 30 to 45 minutes at room temperature.
To soften butter quickly, cut into chunks and allow to soften at room temperature about 15 minutes. If time is limited, place a stick of cold butter between sheets of waxed paper and hit it with a rolling pin on each side to smash butter.
The Land O’Lakes Test Kitchens recommend that you do not soften butter in the microwave for use in baking. The butter can quickly melt even when watched carefully.