Preheat the oven to 180°C and line a loaf tin with greaseproof paper.
Blend the brown sugar and butter in a food processor until fluffy.
Gradually incorporate the eggs one at a time into the mixture.
Simmer dates in water for 6-8 minutes until broken down and water evaporates.
Stir in bicarbonate of soda until dissolved and let cool slightly.
Blend the date mixture into the cake batter until pureed.
Transfer batter to a bowl and fold in the flour.
Bake in the loaf tin for 30-40 minutes until a skewer comes out clean.
Boil 200ml cream, milk, and vanilla, then infuse for 15 minutes.
Beat egg yolks and caster sugar until pale and fluffy.
Whisk the warm milk mixture into the egg mixture continuously.
Strain into a pan and stir over low heat until thickened.
Boil the sauce sugars and 300ml cream in a pan until smooth.
Slice the pudding into eight pieces and soak in toffee sauce for 5 minutes.
Serve pudding slices drizzled with warm custard.