Preheat the oven to 375F. Grease a sponge cake mold with oil or lard and line with parchment paper. Grease the parchment paper as well, ensuring that all the sides are properly covered. Instead of a sponge cake mold, 8 x 175ml-200ml pudding basins can be used as well.
Place the dates, sugar and water in a saucepan and simmer gently for 10 minutes until the sugar has dissolved and the dates are soft. Let cool. Blend dates in a Magic Bullet or similar food processor until smooth.
In a small bowl, sift together the flour, baking soda, baking powder and salt.
In a separate large bowl whisk together the dates, oil, vanilla and espresso. Add eggs and whisk again until well blended.
In two batches, fold into the dry mixture into the wet mixture with a spatula until just combined.
Place all the sauce ingredients into a saucepan and simmer, stirring frequently, until the oil and sugar have dissolved and the sauce is smooth. Reduce sauce until thickened, about 10 minutes. Keep warm until ready to serve.