Every time I make this, I end up changing something. And every time I change something it comes out a little differently, in a good way!
This is my basic recipe:
3 -4 Ancho Chilies
2 tsp Cumin Seed
1 tsp Fennel Seed
2 tsp Garlic Powder
1 tsp Mexican Oregano (or any Oregano if you don't have Mexican)
1 tsp Paprika
(Extera Chilies are a good idea, but I like Ancho for the base. Add in a few extra dried chilies to make it more interesting. Dried Chipotle work great, but some people find them spicy. I like to make smaller batches with around 3-4 chilies total)
Remove the seeds from the Ancho Chilies, and dice them up into 1/2 inch pieces. In a dry pan, toast them over medium heat until you start to hear the seeds crackle and pop.
Transfer everything to a spice grinder and pulse. I like to grind the large bits first, then add the garlic, paprika, and oregano last. Grind for a good 30 seconds to 1 minute.