• Place all pastry ingredients into a food processor and pulse until mixed together (approx. 20 seconds). Transfer pastry onto a silicone bread mat or lightly floured work surface and shape into a disc. Wrap pastry in cling film and place into refrigerator for 45 minutes. After 20 minutes, preheat the oven to 200C/180C fan/gas 6 and place a baking tray (30 x 40cm) onto the oven shelf.
• Meanwhile, prepare the filling - season the trout fillets with salt and put in small saucepan. Add the cream, then remove the stalks from the wild garlic and add them to the pan (reserving the leaves). Bring to a simmer over a medium heat, then cover and remove from the heat. Set aside for 10 minutes to cook through. Put the wild garlic leaves in a colander over the sink and pour over a kettle of just-boiled water to wilt. Leave to drain for 5 minutes, then squeeze out the excess water and roughly chop.
• Lift the trout out of the cream, peel away and discard any skin, then flake into a small bowl. Discard the wild garlic stalks. In a large bowl, whisk the eggs with 0.25 tsp of salt. Pour in the cream from the pan, add the crème fraiche and whisk again, to combine. Stir in the mustard, chives and chopped wild garlic leaves. Season with 0.5 tsp freshly ground black pepper.

Assemble and bake:

• Place the pastry between 2 sheets of floured baking paper and roll out thinly (approx. 5mm thickness). Line the base and sides of a tart tin (24 to 26cm) with pastry and trim the edges.
• Arrange the flaked trout in the pastry case, then pour over the egg mixture. Bake for 35 to 45 minutes until set and golden on top. Leave the quiche to cool in the tin for 15 minutes before serving warm or leave to cool completely.