Cream, a mixer, and ten minutes. No special equipment, no faff, and you'll never look at a butter dish the same way again.
Whip the cream past the usual whipped cream stage, until it curdles and the butterfat separates from the buttermilk.
Drain off the buttermilk, save it for something like the Orange Chocolate Cake.
Squeeze the butter under ice-cold water until the water runs clear, then salt it to taste and shape it however you like.
Best on homemade sourdough, still slightly warm. That's genuinely all you need to make homemade butter.