Step 1Soak the cascabel, guajillo and japones chiles in warm water until softened. Roast the bell peppers over a burner flame or under the broiler, turning them until evenly charred on all sides and soft, about 7 to 10 minutes. Cover them in plastic wrap until cool, then peel and seed. Remove the seeds from the chiles and tomatoes.
Step 2Place the cascabel, guajillo and japones chiles, bell peppers, tomatoes and garlic in a food processor. Puree, adding olive oil as needed for a smooth texture, about 6 tablespoons. The result should be a thick paste. Add salt and pepper to taste.