To make the crumble mixture, combine the flour, sugar, salt and butter in the bowl of a food processor and pulse until the mixture resembles coarse breadcrumbs.
With the motor running, add the eggs and blend until the mixture comes together in a ball. If the mixture looks dry, add the water one tablespoon at a time, allowing it to incorporate, until the dough comes together.
The dough should be soft but not sticky at all, If the dough is too sticky, simply add more flour.
On a floured surface, bring the mixture together into a ball.
Press 3/4 of the mixture into a baking tray (approximately 30cm x 20cm) which has been lined with baking paper.
Wrap the remaining dough in plastic and place both the baking tray and the dough disc in the fridge for 20 minutes.
In the meanwhile, peel and cut the apples into cubes and mix with the sugar and spices and set aside.
Pre-heat the oven to 180°C/350°F.
When the dough has chilled, top the dough in the baking tray with the apples and smooth into a single layer.
Grate/crumble the remaining dough on top then place into the oven.
Allow to bake for 25-30 minutes until the crumble is golden brown and cooked through.
Remove from the oven and allow to cool while you make the salted caramel.
To make the salted caramel, place the sugar in a saucepan over medium heat until the sugar melts. Allow the sugar to caramelize and turn amber in color, gently swirling the pot often to prevent the sugar burning.
Carefully add the butter and cream. The mixture will bubble up aggressively so take care not to burn yourself.
Stir until the butter and cream are incorporated then allow to bubble for another 5 minutes.
Take the pot off the heat then stir in the salt and allow the caramel to cool down. At this stage you can also bottle the salted caramel and keep in your fridge for up to 2 months (however, it will almost definitely not last that long!).
To serve, slice the crumble into bars and serve with a generous drizzle of the salted caramel and vanilla ice cream.