Preheat the oven to 350°F (175°C).

In a saucepan, combine dates, water, and baking soda. Bring to a boil over low heat, then set aside for about 10 minutes until the dates soften. Transfer the dates and water to a food processor and blend into a puree.

In a bowl, cream the butter, brown sugar, and date syrup with a whisk attachment. Add the eggs and continue mixing. Add the flour, baking powder, and salt, and mix until combined. Finally, add the date puree and mix just until incorporated.

Grease a baking pan with butter. Pour the batter into the pan, smooth it out, and bake for about 30 minutes or until golden. Be careful not to overbake.

To prepare the toffee sauce, melt the butter, brown sugar, and date syrup in a saucepan over low heat. Once the sugar is melted, add the heavy cream, whisk, and bring to a boil.

Cut the cake into squares (this step is optional) and pour 2/3 of the toffee sauce over the cake. Use a spatula or spoon to spread the sauce evenly. Set aside to cool. Once set, serve with vanilla ice cream or whipped cream.