WARNING: After pressure cooking, do not remove the jars or open the jars for at least 90 minutes! Open the lids to the jars before they cool can result in burns.
Place the ½ cup of butter into an 8 ounce canning jar. Wipe the rim clean with a paper towel. Put the canning lid on and screw the metal ring onto the jar just finger tight. You want the lid to be secure, but also allow for steam to escape so don't put any strenth into screwing on the metal ring.
½ cup butter
Pour 1 cup of water into the inner pot of the pressure cooker. Place the jar of butter on a rack or in the basket. Make sure it is sitting level so it doesn't tip over.
Put the pressure lid on and turn the valve to seal. Pressure cook on high for 5 minutes. Allow the pressure to natural release. Once the pin has dropped or the display says it is okay to open the lid, turn the pressure cooker off and walk away. Let the jar sit in the pressure cooker for 90 minutes before opening the lid and removing the jar. This is important for safety so no short cuts here.
After the 90 minutes are up, open the pressure lid and remove the jar of clarified butter. You will see that the milk solids are on the bottom and the butterfat is on top.
Pour the butterfat into another jar or container, making sure that the milk solids don't go into the jar. I find that pouring the butterfat works just fine for about 80% of it and then if you want to get the rest, you will want to strain it through a flour sack, cheesecloth, paper towel or coffee filter to catch the milk solids. When straining, pour slowly to prevent the milk solids from going through the towel. I also like to strain into a separate container just in case those milk solids sneak into the butter fat.
Discard the milk solids and what you are left with is a beautiful jar of clarifed butter which can be stored at room temperature, refrigerated, or frozen.