Preheat the oven to 350f ( 170C).
Heat the dates and milk in a small pan for 5 minutes until the dates have softened and you can mash them with the back of a spoon and take off the heat.
Add the brown sugar and butter to the milk mixture. Mix with a spatula until everything has melted. Take off the heat.
In a bowl mix together the flour, baking powder, cinnamon and salt. Stir the wet ingredients into the dry and mix until just combined.
Grease an 8x8 inch (20cm) square baking pan with oil and Line it with an overhang of baking paper.
Pour the prepared mixture in. Spread it evenly with an offset spatula.
Bake for 35-40 minutes or until the sponge is just cooked in the center (this may take longer depending on the size of your pan)
Prepare the toffee sauce. Melt the sugar, butter and cream in a pan. Bring it to a simmer and then allow to boil for 10 - 15 minutes on low heat.
Allow to cool slightly then add sea salt, whisking until it is fully combined. Cool it down.
Pour some all over the cake and reserve the remaining sauce for serving.
Store in an airtight container for 2-3 days. You can also serve it warm with vanilla ice cream. Enjoy!