You can substitute sour cream for butter in refried beans, but this will alter the flavor and texture. Sour cream will add a tangy flavor and make the beans creamier. This could be a delicious variation if you prefer a tangy and creamy taste.

For best results, add the sour cream gradually and taste as you go to ensure it reaches your desired flavor and consistency. Start with a small amount, such as a tablespoon or two, and adjust according to your taste preference.