Use any assortment of chile peppers you like to customize your heat level. Freeze remaining puréed chipotles in adobo in 1-tablespoon portions for easy future us. Also called corn flour (but not to be confused with cornstarch), masa harina is finely ground corn that is most commonly used to make tortillas, but it’s used here to help thicken the chili. Masa harina is widely available in grocery stores, but finely ground cornmeal can be substituted or it can be omitted if you prefer a thinner consistency.