Preheat the oven to 350°F. Grease a 9-inch round cake pan and dust it with flour, tapping out any excess flour.
Place the chopped dates in a large bowl and pour the boiling water over, letting them sit for 5 minutes.
Stir in the brown sugar, oil and egg, using a spatula to blend well and mash up the dates a bit as you blend.
In a separate bowl, sift the flour, cocoa powder, baking powder, baking soda, cardamom and salt. Add this to the date mixture and stir until blended. Stir in the chocolate chips and then scrape the batter into the prepared pan, spreading it to level. Bake the cake for 25 to 30 minutes, until a tester inserted in the centre of the cake comes out clean. Cool the cake for 30 minutes in the pan, then tap it out onto a cooling rack to cool completely.
To serve, dust the cake with icing sugar and slice to serve.
The cake will keep, well-wrapped for up to 4 days, or can be frozen for up to 4 months.