Preheat oven to 160°C (325°F). Line 2 lightly greased 12-centimeter round cake tins with non-stick baking paper, allowing an extra 2 centimeters of paper to overhang at the top of each tin.
Place the dates, water and bicarbonate of soda in a bowl and set aside for 10 minutes to soften slightly.
Place the date mixture, butter, and sugar in a food processor and process until well-combined. Add the eggs, flour, cinnamon, and mixed spice and process until just combined. Divide the mixture between the prepared tins.
Cook for 55–60 minutes or until cooked when tested with a skewer. Allow to cool in the tin for 10 minutes before turning out onto a wire rack to cool completely.
Trim the top off each cake and place each on a cake stand. Using a small palette knife, spread the dulce de leche around the top and sides of the cakes. Decorate the tops with star anise