Step 1: Preheat oven to 425 F.
Step 2: Soak guajillo chiles in very hot water for 10 mins or until they are soft.
Step 3: Cut tomatoes, onion and garlic into large chunks and roast in the oven until the edges begin to char. This could take about 20-30mins.
Step 4: Pulse all the ingredients in a food processor a few times till slightly chunky. Or puree if you like it smooth.
Step 5: Enjoy with tortilla chips, tacos or tamales.