Preheat the oven to 350 degrees Fahrenheit.
Prepare the enchilada sauce first. In a small pot over medium heat, make a roux by whisking the oil and flour until well combined. Add in the tomato paste and cook for about 1 minute. Whisk in the remaining ingredients and let simmer until it begins to thicken, then remove from heat.
In a large saute pan, heat the oil over medium heat and add in the diced onion. Saute for about 5 minutes. Add in the garlic and saute an additional 1 minute. Add in the remaining filling ingredients aside from the cheese and cilantro.
Let the flavors combine for a few minutes, then mix in the cheese and cilantro until the cheese has melted.
To assemble, Spread about 2 tablespoons of sauce onto a tortilla (it helps to warm them up in the microwave for 10-15 seconds to soften before assembly), then layer in the filling. Roll up and place in a 9x13 baking dish. Repeat until all filling mixture has been used.
Spread the remaining sauce on top of the enchiladas and top with the 1 1/2 cups of shredded cheese.
Bake for 20 minutes or until cooked through and the cheese has melted.
Remove from the oven and place on a wire rack. Garnish with cilantro, sliced jalapeno, cotija cheese, guac, pico de gallo etc!