To make the biscuits, preheat the oven to 180oC/Gas Mark 4. Put all the ingredients into a food processor and pulse to fine crumbs. Tip the crumbs into a large bowl and bring together by hand.
Place half of the dough between two sheets of greaseproof paper and roll to the thickness of a pound coin. Remove the top layer of paper and cut out as many rounds as you need, removing and freezing any offcuts with the remaining dough. Slide the rounds on the greaseproof paper onto the baking tray and bake for 10-15 minutes until golden and crispy. Leave to cool on the tray for a few minutes, then carefully transfer to a wire wrack to cool completely.
To make the pudding, keep the oven at the same temperature and line a 20cm (8in) square baking tray with baking paper.
Put the dates in a bowl and pour over 80ml (3fl oz) water from a freshly boiled kettle. Set aside.
In another bowl, cream together the butter and sugar until pale and fluffy. Add the eggs a little at a time, making sure you incorporate well before the next addition. Sieve the flour and bicarbonate of soda into the bowl and carefully fold into the mixture.
Mash the dates up with a fork, then pour into the batter with their liquid. Stir gently to mix in.
Pour the batter into the baking tin and bake for 25-30 minutes, or until a skewer inserted into the middle comes out clean.
Meanwhile, make the sauce. Put the sugar and butter into a small heavy-based saucepan and cook over a gentle heat, stirring until the sugar has dissolved. Whisk in the cream and bring to a boil. Simmer for 1-2 minutes before taking off the heat.
To serve, cut the pudding into equal squares and place into a bowl, pour over the sauce and top with a biscuit. Finish with a dollop of crème fraîche.