Cook the roux and spices: Heat oil in a small saucepan over medium-high heat. Add flour and cook for 1 minute, whisking constantly. Add in the chili powder, garlic powder, cumin and oregano and cook for 1 more minute, whisking constantly.
Simmer: Gradually pour in the stock, whisking constantly to combine until no lumps remain. Continue cooking until the sauce reaches a simmer. Then reduce heat to medium-low to maintain the simmer (the sauce should continue lightly bubbling) for about 10-15 minutes, uncovered, until the sauce has slightly thickened.
Season: Give the sauce a taste and season with salt, as needed. (I typically add 1/2 teaspoon fine sea salt, but the saltiness of the sauce can vary depending on the brand of stock that you use.
