Step 1

1 In a large, heavy skillet set over medium heat, heat the oil until shimmering

Step 2

2 Add the bell peppers and chiles and cook, stirring, until the bell peppers shrivel and the chiles darken, about 15 minutes

Step 3

3 Remove from the heat and let cool completely

Step 4

4 Transfer the mixture to the pitcher of a blender, add the salt and tamarind paste and process until smooth

Step 5

5 If the ingredients are too thick to begin blending, add a little water, 1 or 2 teaspoons at a time, to facilitate

Step 6

6 Transfer to a lidded container and use right away, or refrigerate until needed