I love to slice a piece of the butter and top it on hot waffles,pancakes,etc,no need to thaw first.
Turn mixture out onto a long sheet of plastic wrap set over a long sheet of foil. Use the wrap/foil to roll the butter into a cylinder: first seal the plastic wrap around the cylinder, then secure the foil around it. Twist the ends, gradually applying more pressure as you twist in order to make the cylinder taut.
Once it's a nice, neat cylinder of foil, place into the freezer for 30 minutes in order to quickly solidify it, then transfer it to the fridge until you're ready to use it. Butter should be nice and firm. Keep in freezer for long term use.