Place butter in a medium saucepan and melt completely on low heat.
Simmer without letting it brown, until the surface is completely coated with foam.
Skim off the foam as it rises to the surface while cooking until nothing more remains.
It should look quite transparent. Now, add all the ingredients: onions, garlic, ginger cumin, cardamon, oregano, turmeric, nutmeg, and basil. Continue cooking on low heat for about 15- 20mins.
Pass it through a cheesecloth or sieve. It is now ready to be used. Store in a tightly covered container for about a month in the fridge.