Heat oil in a small saucepan over medium-high heat. Add flour and stir together over the heat for one minute. Stir in the remaining seasonings (chili powder through oregano). Then gradually add in the stock, whisking constantly to remove lumps. Reduce heat and simmer 10-15 minutes until thick.
Use immediately or refrigerate in an air-tight container for up to two weeks.
I also enjoy substituting 1-2 Tbsp. of chipotle powder in place of some of the chili powder.