Step 1Place the dried chiles in a small saucepan and fill with enough water to just cover the chiles. Bring the water to a boil over high heat, then reduce the heat and simmer for 5 minutes. Remove from the heat and allow the chiles to soak until thoroughly softened. Drain the water and coarsely chop the chiles.
Step 2Place the butter in a medium bowl and whisk until it is light and creamy.
Step 3Bruise the cumin seeds using a mortar and pestle. Whisk them into the butter. Using the mortar and pestle or a food processor, puree the garlic and add it to the butter. Puree the chiles the same way and add them to the butter to taste. Season to taste with salt. The butter can be served right away or refrigerated up to a week.