Preheat the oven to 350 degrees. Grease and flour a 9 inch springform pan and place it on a rimmed baking sheet. Set aside. Combine dates and baking soda in a bowl and cover with boiling water until submerged. Cover and let sit for 30 minutes to allow the dates to soften. Drain the dates and set aside.
Meanwhile, whisk salt, baking powder, cinnamon, cardamom, flour and rye flour together in a large bowl. Set aside.
Whisk the sugar, brown sugar, vanilla extract and oil together in a medium bowl. Add one egg at a time, whisking thoroughly until fully incorporated before adding the other egg.
Fold the wet ingredients into the dry ingredients, Mixing until just combined. Add the dates and mix until they are evenly distributed throughout the batter.
Spoon the mixture into the prepared springform pan. Smooth the top with a small offset spatula or the back of a spoon. Bake until a skewer inserted into the center of the cake comes out clean and the cake is firm to the touch in the center, about 40-45 minutes.
Allow to cool before removing the sides from the pan. Serve warm or at room temperature with 3 Ingredient Salted Caramel Sauce if desired.