Dissolve the baking soda in water and pour it along with hot tea, just enough to cover the dates.
Let the dates soak in this for about 6 hours.
Mash the partially dissolved dates until you’ve reached a paste-like consistency and set them aside.
Next, mix the flour and baking powder in a medium-sized bowl, and set aside.
Beat the butter using a stand-alone or handheld mixer on high speed for about a minute, until smooth.
Add the sugar to the butter and cream together for about two minutes.
In a separate bowl beat the eggs thoroughly then add them a little at a time to the creamed mixture, beating well after each addition.
Beat the vanilla together with the creamed mixture, then add in the mashed dates and beat.
Lastly, stir in the cashew nuts and ground cardamom.
Preheat the oven to 350 F.
Grease a round cake baking pan, and transfer all the batter into it spreading evenly. Bake for 30 – 35 minutes. Insert a toothpick into the center of the cake to make sure it comes out clean, before removing it from the oven and setting it out to cool.