
Chicken enchiladas are an easy way to use up extra or leftover chicken. A homemade sauce is well worth the effort for this tasty bake.
Make sauce: Heat oil in a medium saucepan over medium heat. Add garlic, chipotles in adobo, and tomato paste. Cook, stirring often, until dark maroon in color, 2 to 3 minutes. Add cumin and chili powder. Cook, stirring, 30 seconds. Add stock and bring to a simmer. Transfer 1/4 cup stock mixture to a bowl and whisk in corn starch. Return slurry to pot and stir to combine. Bring to a boil then reduce to a simmer. Cook until slightly thickened, 3 to 5 minutes. Stir in vinegar and season with salt. Transfer mixture to a blender and process (with the plastic cap removed and a dish towel covering the opening) until smooth, about 30 seconds. Transfer 1/2 cup sauce to a bowl. Add chicken and toss to coat, reserve remaining sauce.