Step 1: Soften the Raisins - Pour 1 cup of boiling water over 1/2 cup of raisins in a heatproof bowl. Let them soak for 15 minutes, then drain excess water.

Step 2: Blend the Base - In a food processor, combine the softened raisins, 1/4 cup unsulfured molasses, 2 tablespoons tamarind paste, 2 anchovy fillets, 1 chopped onion, 1 tablespoon grated fresh ginger, 2 minced garlic cloves, and 1/4 cup of white vinegar. Blend until smooth.

Step 3: Cook the Mixture - Transfer the blended mixture into a medium saucepan over medium heat. Add remaining ingredients: 1/2 cup white vinegar, 1 teaspoon cardamom pods, 1 teaspoon kosher salt, 2 tablespoons brown sugar, 1/2 teaspoon crushed red pepper flakes, 1 teaspoon dry mustard, 1/4 teaspoon whole cloves, 1/2 teaspoon black peppercorns, and 1/4 teaspoon ground cinnamon. Stir and bring to a gentle boil, then remove from heat.

Step 4: Store the Sauce - Pour the hot mixture into a sterilized jar while still warm. Secure the lid and store in a cool, dark place for at least one month.

Step 5: Final Preparation - After one month, strain the sauce through a fine mesh sieve and store in the refrigerator.