You can make schmaltz at home easily. Here’s what you need:
2 cups finely chopped chicken skin and fat
1/4 cup water
1 yellow onion, diced, optional
Place about two cups of finely chopped skin and fat in a saucepan with a quarter cup of water. Bring the mixture to a simmer over high heat before reducing the heat to low.
Stir the mixture from time to time. After about 90 minutes, the skin should be nice and crispy. Add a diced onion (if using) and continue to cook the schmaltz until the onions are golden brown.
Strain out the rendered fat through a piece of cheesecloth (saving those delicious little bits of crisped-up skin called gribenes to enjoy as a snack). Store the schmaltz in the refrigerator or freezer, tightly wrapped in plastic wrap to prevent it from taking on other flavors in the freezer.