Jersey Royal, wild garlic & watercress tart with pink pickled onions

Method

• step 1

  First, make the pickled onions. Put the onion in a bowl, then bring the vinegar, sugar, salt, mustard seeds and 50ml water to a boil in a saucepan. Stir, on a medium heat, to dissolve the sugar. Once dissolved, remove from the heat and pour over the onions. Set aside for at least 30 mins.

• step 2

  Meanwhile, make the pastry. Mix the flour with a pinch of sea salt in a bowl. Add the butter and use your fingers to lightly bring it together to a breadcrumb texture. Don’t worry if there are some big chunks, this will help make it light and flaky. Stir in the vodka, then pour over 2 tbsp ice cold water and use a butter knife to bring the dough together. Use your hands to form into a ball. If it needs more liquid, add a dash more iced water. Turn out onto a floured worksurface and knead briefly, until smooth and pliable. Squash it into a disc, then wrap in baking parchment and chill for 30 mins.

• step 3

  Heat the oven to 200C/180C fan/gas 6. Put the potatoes and mint in a saucepan and cover with cold water. Add a big pinch of salt and bring to the boil, then simmer for 10 mins until tender. Turn off the heat and allow the potatoes to cool in the water.

• step 4

  Roll the pastry out until about 5mm in thickness, then transfer to a loose-bottomed 20cm tart tin. Trim the edges with a knife, then chill for 10 mins until firm. Prick the base with a fork, line with crumpled baking parchment and fill with baking beans or rice. Bake for 20 mins.

• step 5

  Remove the baking beans and parchment. Whisk one of the eggs in a bowl, then brush all over the pastry. Bake for 10 mins more, then remove from the oven.

• step 6

  Blitz the remaining eggs and egg wash, the wild garlic, watercress and cream to a purée in a food processor. Transfer to a bowl and stir in the drained ricotta and lemon zest. Add most of the cheese, nutmeg and a pinch of salt. Slice the potatoes into bite-sized pieces and arrange half of them in the tart case. Using a teaspoon, dot in the harissa. Pour over the green egg mixture and nestle in the remaining potatoes. Scatter over the rest of the cheese.

• step 7

  Bake for 35-40 mins. Allow to rest for at least 20 mins before you remove it from the tin and slice. Serve with a watercress salad, if you like, and the pink pickled onions.