Tostar (Dry-Roasting)

This is often the very first step in preparing a Mexican dish. It is how I char the dried chiles and bloom the spices I use in my moles. Oils were not introduced to Mexico until the arrival of the Europeans, so the Aztecs used this dry-heat method to seal in the flavor of—and get the most flavor out of—chiles, tomatoes (red or green), and tomatillos, primarily for salsas.

Rinse and dry the chiles, then roast them on a very hot comal or dry cast-iron skillet over high heat, turning as needed. A bacon press or large metal spatula can be used to make sure all parts of the chile are touching the hot surface. Remove them from the heat before they begin to change color (unless a recipe specifies otherwise). If they darken too much, their flavor can become bitter.