Jessica Prentice's Niter Qibbeh, an Ethiopian Spiced Ghee

From Jessica Prentice's Full Moon Feast (p. 117):
Niter Qibbeh (Ethiopian Spiced Ghee)
Makes about two cups

This classic cooking oil of Ethiopia is a great thing to use whenever you want to give something a more complex North African or Middle Eastern Flavor. It is also a primary ingredient (along with the spice mixture berebere) of Ethiopian cooking.

1 pound butter
1/2 onion, cut into coarse slices
2 cloves garlic, coarsely chopped
4 slices gingerroot, each about the size of a quarter
4 slices fresh turmeric root, each about the size of a dime--or 1/2 teaspoon powdered turmeric
4 pods cardamom, each one pounded once so that the pod cracks open (you can do this in a mortar and pestle or on a cutting board using a meat pounder or a hammer wrapped in a towel)--or 1/2 teaspoon ground cardamom
1 cinnamon stick, broken into a few pieces
2 cloves
1/4 teaspoon whole fenugreek seeds
1 tiny chunk of nutmeg

1. Melt the butter in a cast-iron pan over low heat until it begins to foam.
2. Add the remaining ingredients to the butter and cook over low heat until the surface is clear. This could take anywhere from 20 to 45 minutes.
3. Turn off the heat. Pour the niter qibbeh through a fine-mesh strainer or a strainer lined with cheesecloth into a jar.
4. Let it cool and then transfer to the fridge. It will keep for several months.