01 - Preheat oven to 350°F. Grease and line an 8-inch square baking dish.
02 - Place chopped dates in a bowl, add boiling water and baking soda. Stir and let stand for 10 minutes until softened.
03 - In a large bowl, cream together softened butter and light brown sugar until light and fluffy. Beat in eggs one at a time, then incorporate vanilla extract.
04 - Sift flour, baking powder, and salt together. Gradually fold dry ingredients into the creamed mixture.
05 - Lightly mash softened dates with a fork and add the mixture, including liquid, to the batter. Mix gently until just combined.
06 - Pour batter into the prepared baking dish and smooth the top. Bake for 35 to 40 minutes, or until a skewer inserted in the center comes out clean.
07 - In a saucepan, combine brown sugar, butter, heavy cream, golden syrup, vanilla extract, and salt. Heat gently, stirring until butter and sugar dissolve. Increase heat and simmer for 3 to 4 minutes until thickened.
08 - Once baked, pierce the sponge all over with a skewer. Pour half of the warm toffee sauce over the top and allow to soak for 10 minutes.
09 - Cut sponge into portions and drizzle with remaining warm toffee sauce. Optional: Serve with vanilla ice cream or custard.