METHOD
1. Place the dates in a saucepan with the water and bring to the boil. Take the pan off the heat, stir in the soda and set aside to cool.
2. Preheat the oven to 180C/350F/gas 4. Line a square 20 x 20cm cake tin with parchment.
3. Beat the butter with the sugar until smooth and fluffy, scraping the sides of the bowl every so often. Beat in the egg and vanilla, ignore the curdling.
Blitz the cooled dates and the liquid with a stick blender or in a food processor; stir in the grated apples. Add the date and apple mix into the cake batter and beat it in briefly. Stir the flour and baking powder together and fold into the batter.
4. Pour the mix into the prepared tin and smooth the top with a spatula. Bake for 40 – 50 minutes, until a skewer inserted into the middle of the cake comes out with just a few crumbs stuck to it.
5. Remove the cake from the oven and cool in the tin.
6. In the meantime place the butter and sugar in a saucepan on medium heat. Cook and stir until mixture turns a deep yellow colour. Carefully stir the cream and vanilla into the butter and sugar mixture. Whisking constantly, cook until sauce thickens and coats the back of the spoon.
7. Sprinkle the nuts over the cake and spoon the sauce over the nuts. Leave to set.
8. To serve, cut the cake into squares and serve drizzled with the sauce; you can warm the cake up in the microwave before serving.
9. If the sauce sets too much (keep it at room temperature), warm it very gently over low heat. If it separates, beat in a tablespoon of cream.