Measure the butter into a small glass bowl. Heat the butter in the microwave oven for about 7-8 seconds or until nearly melted, or carefully melt it in a small skillet over a low heat until just melted but not browned. Whisk in the smoked paprika, mixing until completely blended.
Taste before adding salt; if you used salted butter, you may not need much additional salt. Turn the butter into a small bowl, using a rubber spatula to scrape the bowl or the skillet. Serve soft or chill until firm. You can store the butter in the refrigerator for up to 3 days.