Method

1. To make the pastry, tip the flour into a large bowl, add 1/ 2 tsp salt and mix through with the cayenne and mustard powder. Add the butter and use your fingertips to rub it into the flour until the mixture resembles damp sand. Mix through the cheese, then drizzle in 2-3 tbsp cold water. Squash the crumbs together until you have a smooth ball of pastry, tip onto your work surface and knead a few times to incorporate any dry crumbs. Wrap in cling film, pat into a flat disc shape and chill for at least 30 mins. Can be made up to a day before (or make and freeze for up to two months).

2. While the pastry chills, put the potatoes in a pan of cold, salted water, bring to the boil and simmer for 10-12 mins or until tender – a knife should easily pierce the potatoes when they are cooked. Drain and set aside until cool enough to handle. Slice the potatoes into 0.5cm discs and set aside to cool completely.

3. Remove the pastry from the fridge 10 mins before you’re ready to roll it. Heat oven to 180C/160C fan/gas 4, with a baking sheet heating up on the middle shelf. Lightly flour the work surface and roll the pastry until it’s large enough to line a deep 23cm fluted tart tin – the pastry should be about the thickness of a £1 coin. Carefully lift the pastry into the tin and press it into the corners, patching up any holes with spare scraps of pastry. Trim the excess with a pair of scissors, but leave about 1cm overhanging. Line the case with baking parchment (it'll be more pliable if you scrunch it up in your hands first) then fill with baking beans. Place on the baking in the oven and bake for 15 mins, then remove the beans and parchment and return to the oven for a further 10 mins or until biscuity. Use a small serrated knife to trim the pastry flush with the tart tin. Reduce the oven temperature to 160C/140C fan/gas 3. 

4. Mix the eggs, yolk, cream, milk, mustard and nutmeg in a jug with some seasoning. Toss the cooked potatoes, shrimps, herbs and some seasoning in a bowl, then pack into the tart case. Pour in the egg mixture, filling with the last few drops once the tart is back in the oven, to avoid spillages. Scatter with a pinch of cayenne, then bake for 50-55 mins or until just set- give the tart a shake, it should still have a slight wobble in the centre. Leave to cool to room temperature. 

5. Now make the salad. Wear rubber gloves to peel the beetroot (to stop your hands straining), then slice as thinly as you can, using a mandolin if you have one. Whisk the oil, mustard and vinegar with some seasoning, and drizzle over the beets, then toss together. Serve on top of the cooled tart, or on the side in a big bowl, scattered with cress.