1 dried chile de árbol or other dried red chile, stemmed and crumbled
1 bay leaf
1 1/3 cups golden raisins (1/2 pound)
3 thyme sprigs
1 small rosemary sprig
1 teaspoon kosher salt
In a small saucepan, toast the mustard seeds over moderate heat, shaking the pan, until the seeds just start to pop, 2 minutes. Add the remaining ingredients and bring to a boil. Reduce the heat to low and simmer gently until the liquid has reduced by half, about 8 minutes. Let the raisins cool completely. Drain before serving.
The raisins can be refrigerated in the pickling liquid for 3 days.