homemade enchilada sauce

I made some delicious Cuban pork last night for a Mexican buffet and decided to put together a casserole for tonight.  I decided to try to make an enchilada sauce and I love how it turned out.  So easy to make!  Below is a double batch which makes 4 cups.  I figure I will always need at least 4 cups.

homemade enchilada sauce (Cookie and Kate)
6 tablespoons olive oil
6 tablespoons flour (I used whole wheat)
2 tablespoons ground chili powder
2 teaspoons ground cumin
1 teaspoon garlic powder
1/2 teaspoon dried oregano
1/2 teaspoon salt, to taste
1/4 cup tomato paste
4 cups vegetable broth (I used chicken broth)
2 teaspoons distilled white vinegar
freshly ground black pepper, to taste

This sauce comes together quickly once you get started so measure the dry ingredients into a small bowl and place it near the stove.  Place the tomato paste and broth near the stove as well.
In a medium-sized pot over medium heat, warm the oil until it's hot. Pour in the flour and spice mixture.  While whisking constantly, cook until fragrant and slightly deepened in color, about 1 minute.  Whisk the tomato paste into the mixture, then slowly pour in the broth while whisking constantly to remove any lumps.
Raise heat to medium-high and bring the mixture to a simmer, then reduce heat as necessary to maintain a gentle simmer.  Cook, whisking often, for about 5-7 minutes, until the sauce has thickened a bit.
Remove from heat then whisk in the vinegar and season to taste with a generous amount of ground black pepper.  Add more salt if necessary.