Use a mason jar. Fill half way , for room to shake.. Shake for 15 to 20 minutes,( at this point make sure the lid tight, and let you kids do the work) ;) until milk and butter separate.strain, keep milk for other recipes.. run butter under cold water to make soild. Wrap in plastic wrap until completely soils..
note: If you like to make flavored butter, add your ingredient , (roasted garlic and basil, dried tomatos, etc) do it after you sperated the butter, then roll in plastic wrap and chili to soild..