Coat a large nonstick skillet with cooking spray and place over medium heat. Add onion and cook, stirring often, until soft, about 2 minutes. Add garlic; cook, stirring constantly, for 20 seconds more. Add chiles; cook, stirring constantly, for 30 seconds. Add water and immediately turn off the heat. When the water stops boiling, pour the chile mixture into a small bowl. Make sure all the pieces are submerged; cover and set aside to soften, 20 minutes.Advertisement
Pour the chile mixture into a food processor or large blender. Add pepitas, thyme, cumin and salt. Pulse a few times, then process until smooth, or to the desired consistency, scraping down the sides occasionally.
Ingredient Note: Dried New Mexico chiles are sweet with a hint of spiciness. They can be found in the specialty-produce section of the supermarket, in gourmet-food markets or online at www.melissas.com.
Tip: To toast pepitas, cook in a small dry skillet over medium-low heat, stirring constantly, until fragrant and lightly browned, 2 to 4 minutes.