Heat oil in a large saucepan over medium-high heat. Add onion, chile peppers and garlic and cook, stirring, until the onion is soft and beginning to brown, 3 to 4 minutes.Advertisement
Reduce heat to medium. Add tomatoes, chili powder, cumin, salt and cayenne. Cook, stirring occasionally, until the tomatoes have broken down and thickened slightly, 6 to 8 minutes.
Carefully transfer the tomato mixture to a food processor or blender. Pulse to make a chunky sauce, or until desired consistency. (Use caution when pureeing hot ingredients.)
Let cool to room temperature, about 1 1/2 hours. Stir in cilantro and lime juice just before serving.
Make Ahead Tip: Prepare through Step 3. Cover and refrigerate for up to 5 days or freeze in an airtight container for up to 6 months. Stir in cilantro and lime juice just before serving.
Shopping tip: Ancho chile, a dried poblano pepper, is one of the most popular dried chiles used in Mexico. It has a mild, sweet, spicy flavor. Find ground ancho chili powder in the specialty spice section of large supermarkets.
1 1/2 vegetable, 1/2 fat