I have used readymade tamarind pulp. But you could soak tamarind and dates separately in warm water. Remove their seeds chop red chilies grind all into a processor until they blend well.Take a heavy bottomed sauce pan add both tamarind and dates pulp. Also add jaggery granules + water. Cook for 10 mins keep stirring. Once the mixture reduces and gets thicker switch off the gas.Strain the mixture with a mesh strainer Or siever. Discard the leftover pulp. Add chat masala, black salt, roasted cumin powder and lemon juice if using. Alter any spices if required add salt for seasoning. Serve Dates Chutney chilled Or at room temperature with chat Or patties.