Preheat the oven to 180C. Base-line a deep 23cm/9 in round cake tin with non-stick baking paper.

Place the potatoes in a large saucepan and cover with cold water. Bring to the boil and cook for 10 minutes. Drain well and allow to cool slightly before slicing thinly.

Wash the spinach and place in a large pan with only the water that is clinging to the leave. Cover and cook, stirring once, until the spinach has just wilted. Drain well in a sieve and squeeze out the excess ,moisture with the back of a spoon. Chop the spinach  finely.

Beat together the cream cheese, mustard and eggs, then stir in the chopped spinach and fresh herbs.

Place a layer of sliced potatoes in the lined tin, arranging them in concentric circles. Top with a spoonful of the cream cheese mixture and spread out. Continue layering, seasoning with salt and pepper as you go, until all the potatoes and the cream cheese mixture are used up.

Cover the tin with a piece of foil, scrunched around the edge, and place in a roasting tin.