For the pastry:
For the filling:
Start with preparing the dough by rubbing in with your fingers all the ingredients and kneading the pastry until well combined. Form a bowl, cover it in cling film and leave in the fridge to rest for a minimum of 30 minutes.
Grease a loose bottomed tart tin of 26-28 cm in diameter (with the borders not too high) with butter.
Take the pastry from the fridge and roll it out. Place it in the tin and gently press the dough onto the bottom and inside of the baking dish. Trim the edges by rolling a rolling pin over the tart tin. Prick the bottom with a fork, line the dish with baking parchment and fill with dry beans or rice (this process will prevent the pastry for rising).
Place the baking tin in a preheated oven to 180 C and bake blind for 10-15 minutes.
Take it out and remove the baking parchment, leave to cool.
Now prepare the filling.
Place the sugar in a pot and set to cook on a medium heat. Don’t stir the melting sugar, wait until it fully dissolves and starts to bubble. From the translucent liquid it should change its colour into a golden, light brown. Be careful not to burn as it is very easy and quick do at this stage.
In the meantime warm up the cream in a separate pan.
Turn the heat down of the pan with the sugar and add the butter (which stops the sugar from caramelising). Once the butter has melted add the cream while stirring gently. Carry on cooking (on a low heat) and make sure there are no lumps of sugar (in case there are any, carry on cooking the liquid until the sugar fully dissolves). Now add to the caramel the chopped walnuts and the honey if using (I like to use chestnut honey for an extra autumnal feel). Cook everything for a few minutes.
Give the walnut mixture a stir and now pour everything into the pastry case. Even out the surface and bake in the preheated oven to 180 C for 30-35 minutes.
Take the crostata out from the oven and allow 60 minutes for it to rest and cool down before serving.
It works beautifully with some vanilla ice cream on the side.