Homemade curry powder is such a cheap and simple thing to make, I don't know why people don't make their own more! Store bought curry powder often has colours, additives and preservatives, so making your own enables you to know exactly what you are putting in your cooking.
I don't generally insist that people choose organic produce when cooking, but when it comes to herbs and spices there really is a huge difference! Spices will last up to 12 months when stored in an airtight container, so despite being a bit more expensive, you will still get bang for your buck. And did you read the Choice review that talked about the actual percentage of oregano that was in common/popular brands of herbs? Make sure you buy reputable brands such as Gourmet Organic Herbs or by bulk herbs online from Honest to Goodness or shops like Terra Madre (if you live in Melbourne).
This curry powder will make enough for 5-8 curries (depending on how strong you like your curry) and will last approximately 12 months in an airtight container.
In a bowl, combine:
4 tsp cumin ground cumin
4 tsp ground coriander
3 tsp turmeric powder
2 tsp mustard powder
1 tsp cardamom powder
½ tsp ground cinnamon
Place in an airtight container and store away from heat and direct sunlight.