Measure out dates, then coarsely chop. In a medium microwaveable bowl, add 1/4 cup water and microwave on high for 50 seconds. Stir in the chopped dates and baking soda. Stir to combine, then let stand for 5 minutes. After 5 minutes, add the butter to the bowl with the dates and let it sit in the warm liquid for another 5 minutes.
Make the sauce by combining the butter, brown sugars and cream in a medium microwavable bowl. Microwave on HIGH for 30 seconds. Remove and stir for 15-20 seconds or until butter is melted. Return to the microwave and microwave a further 30-45 seconds or until the sauce coats the back of a spoon. Set aside for now.
After the dates have stood for the second 5 minutes, stir to combine (butter should be all melted). Add the brown sugars and egg, if using and stir in to combine. Add the flour, baking powder and a pinch of salt. Stir until flour is all mixed in.
Divide the batter between two microwave safe mugs or small bowls. Microwave on HIGH for 2 minutes uncovered. Test with a skewer to make sure the cake is set. (If not, microwave more in 15 second increments until set). Use a skewer to poke some holes in the cakes and run it around the outside as well, to make some space for the sauce to fill down the sides. Pour toffee sauce over-top. Garnish with some pecan pieces, if desired. ALLOW TO STAND A FEW MINUTES before eating, to allow the sauce to cool a bit and the cake to set-up and the sauce to soak in. **Important that you let it stand. That sauce can be very hot!!
Enjoy warm with a scoop of ice cream, if desired.
Notes
To get 1/2 an egg, break an egg into a small cup and stir together with a fork. Use 1/2 of the mixture.