If you have an electric meat grinder, and a coarse plate, the coarse plate I have is called the wagon wheel. Assemble your grinder with clean sterile parts. Do not add the hopper tray, the try that fits on top of the feed tube, first, it is not needed, two, less to wash later.
To prepare the fat, you want is very cold, not frozen. Place the fat skin side up on a cutting board, cut into strips that are about ⅜ inch wide, once all the strips are cut, check each one for any meat tissue and trim that off. Be careful doing this as pieces will be very slippery. Here you can see the strips and the meat tissue I removed on the right.
Place a bowl to catch the fat. For this method, you are not going to load up the hopper with a bunch fat, you are going to do this one strip at a strip at a time, as the grinder is grinding the skin as well, so we do not want to overwhelm the grinder or slow the motor. Turn the grinder on and drop in a fat strip, when that is coming out, drop in another. This actually goes quite fast.
Place the fat in your slow cooker. And proceed with adding the 1/4 cup of water and setting the cooker to Low.
Stir every hour, the fat and skin will turn golden brown and the bits will sink to the bottom, when they start to float, the lard is ready. Mine was ready after 9 hours.
Pour the lard through cheese cloth placed in a strainer, over a pot, Let the brown bits drain for about 20 minutes or so. Remove the strainer and discard the bits, they are so small, don't worry about using them.
Pour the lard into a quart jar and allow to cool on the counter uncovered. Once cooled, cover and store in the fridge until use.