Mix the flour, sugar, butter, egg and salt together to form a dough for short crust. Form a large ball and let it rest for 30 mins covered in the fridge.
In the meantime chop the nuts coarsely.
Mix the sugar and the water at full heat until it starts to boil. Stir frequently and once the water has started to dissolve the sugar, mix the nuts into the sugar. Reduce to medium heat and keep stiring until the sugar starts to get more syrupy. Be aware that you might need to adjust the heat: you don't want the caramelised nuts to become to sticky in the pan. Add the liquid cream and continue to stir for another 4-5 minutes.
Roll out half of the dough for the bottom of the cake. Make sure you pull the sides up a bit before pouring the nuts onto the dough. Cover the cake with the other half of the rolled-out dough and poke a few holes with a fork into the cover.
Bake for about 30 minutes at 180 degrees until the top is brown. You might need to adjust the source of the heat to ensure that especially the bottom of the cake is nice and crunchy.