Put the flour, butter and salt in the food processor and mix until you have crumbs like consistency.

Add cold water and pulse until you get the dough.

Turn out onto floured surface and shape into disc. Cover with cling film and chill in the fridge for at least 15 min.

Preheat the oven to 200°C.

Roll out the pastry to fit loose-bottomed tin (23-25cm). Line the tin with pastry (bottom and sides) and trim any overhanging bits with the stroke of a knife against the edge of the tin. Save for later in case you need to patch any holes.

Line pastry with baking paper and fill with baking beans (blind baking). Bake on a baking sheet in preheated oven for 15min.

Remove the paper and beans and brush bottom of the pastry lightly with beaten egg which will create a seal. Bake for another 5 mins. Set aside.

Turn oven down to 180°C.

To prepare the filling take the skin off the mackerel, tear the fish into small pieces and scatter them evenly over the pastry.

Put cream, beaten eggs, horseradish, chives/spring onions and pepper into the large jug and mix vigorously.

Pour the mixture over the mackerel and bake for 30-35 min until set and golden in colour.

Let it stand for 10 minutes before removing from the tin. Best eaten slightly warm or room temperature.

Enjoy!