Step 1

Bring a medium pot of water to boil. Add guajillos and reduce heat to a simmer. Cook for about 25 minutes, or until softened.

Step 2

Remove chiles from water and place in a blender along with the garlic, onion, brown sugar and one of the tomatoes. Blend on high until smooth, about 1 minute. Add the remaining tomatoes and blend on high until tomatoes are incorporated, about 30 seconds.

Step 3

Season to taste with salt and pepper.