Preheat oven to 160°C (325°F). Place the dates, water and bicarbonate of soda in a bowl and set aside for 5 minutes. Place the date mixture, butter and sugar in a food processor and process until well combined. Add the eggs and flour and process until just combined.
Pour the mixture into a lightly greased 20cm-square tin lined with non-stick baking paper and bake for 60–70 minutes or until cooked when tested with a skewer. Allow to cool in tin for 10 minutes before turning out onto a wire rack.
To make the toffee sauce, place the butter, cream and sugar in a saucepan over medium heat and stir until the sugar is dissolved. Bring to the boil and cook for 8–10 minutes or until thickened slightly. Serve with the sticky date cake warm or at room temperature. Serves 6–8.