Step 1: Preheat your oven to 350°F (175°C) and grease a 9-inch springform pan with butter or line it with parchment paper.
Step 2: In a medium heat-proof bowl, combine the chopped dates and baking soda. Pour the boiling water over them and let soak for 15 minutes until softened.
Step 3: In a large mixing bowl, cream together the softened butter and brown sugar until the mixture is light and fluffy.
Step 4: Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Step 5: In a separate bowl, whisk together the almond meal, all-purpose flour, baking powder, cinnamon, and salt.
Step 6: Gradually add the dry ingredients to the butter mixture, alternating with the date mixture (including the soaking liquid), and stir until just combined.
Step 7: Pour the batter into the prepared pan and smooth the top. Sprinkle the flaked almonds evenly over the surface.
Step 8: Bake for 40-45 minutes, or until a skewer inserted into the center comes out clean.
Step 9: Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.