Melt butter in a deep large saucepan over medium heat. Whisk in flour and let cook for 30 seconds.
While whisking slowly add in the tomato sauce, chili powder, garlic powder, salt, cumin, and oregano. Add in a quarter of your finely chopped chipotles. (see notes)
Slowly whisk in the veggie stock.
Take a spoon and carefully taste test the sauce. If you would like the sauce more spicy add in more of your chopped-up chipotle peppers. Keep taste testing until you reach your desired spice level for the sauce.
Use right away, or place in a jar and refrigerate for up to 5 days or freeze in a freezer bag for up to 6 months.
Notes
Not all peppers are considered equal, some chipotles are spicier than others even if they are in the same can. I recommend finely chopping up 2 peppers and slowly adding them in the sauce taste testing after every add to ensure your sauce won't be too spicy.