This thick, tangy, sweet-n-hot sauce goes beautifully with samosas, lentil fritters, pack potatoes, pakoras and such savoury snacks. It's easy to prepare and can be made in bulk up to 2 weeks in advance and any leftovers can be refrigerated.
Soak the tamarind pulp (seeds and all) in the 2 cups of boiling water, stir, cover and set aside for 30 minutes.
Mix and straine the softened soaked mixture, pressing it through a fine-meshed strainer to extract all the juices and discard the seeds plus any other solids.
Pour this strained tamarind juice into a pan and add the brown sugar and the salt. Simmer on low heat for 15 minutes. Allow this to cool slightly.
In the meantime, have all the other ingredients ready. Put the chopped/grated mango, soft dates, chillis, garlic, ginger, vinegar and ketchup into a food processor. Add the cooled tamarind juice to the rest of the ingredients. Process until thick and combined. Give it a taste and adjust by adding more dates or extra ketchup for sweetness, salt if needed or chillis for extra heat.
You can use a blender if you do not have a processor. I like the slightly textured results from a processor as opposed to the very smooth results from a blender.
The flavours develop further the longer this dip sits, so it's ideal to prepare it a few hours or up to a day before you serve it.