If you don't have a blender, mince the onions, garlic and ginger. Sauté the onions slowly for 10 to 15 minutes until soft and translucent, then add the curry powder, cumin, turmeric, ginger and garlic. Cook for a few more minutes until you can smell the spices, and they've incorporated well into the mixture. Make sure not to overfry the spices, this process takes maybe a minute or so max.