MAKE THE PASTRY: Weigh the flour into the bowl of a food processor with the blade attachment fitted. Add the salt, butter and lard, then pulse until the mixture resembles fine breadcrumbs. Add the egg yolk and 2-3 tablespoons of milk, then run the processor until the mixture clumps together into a ball of dough, adding a little extra milk if the pastry is too dry. Turn onto a lightly floured work surface and shape it into a flat disc.

PREPARE PASTRY CASE: Grease a deep-sided 24cm pie dish, loose-bottomed flan, or tart tin (see notes). Roll the pastry out to an even circle, slightly larger in diameter than the dish you are using. Lift the pastry into the dish and press gently into the sides. Trim the edges as necessary, prick the pastry base with a fork, and then transfer to the freezer for 20 minutes. Reserve any remaining dough for patching any cracks in the blind-baked case.

PREPARE THE FILLING: While the pastry is chilling, heat the oven to 200°C / 400°F / Gas 6 with an oven tray or baking sheet in the middle to lower third. In a large mixing bowl, gently whisk the milk, creme fraiche, eggs, tarragon, garlic, spring onion, salt and nutmeg. Set aside to infuse.

COOK THE VEGETABLES: Bring a large pot of lightly salted water to the boil. Cook the beans for a few minutes until tender, then lift out with a slotted spoon and refresh under cold water. Set aside. Add the spinach to the pot, stir and leave to blanch for 2-3 minutes, then drain and refresh under cold running water. When the spinach is cold enough to handle, use your hands to squeeze out as much water as you possibly can, then wrap it in a paper towel and set aside.

BLIND BAKE PASTRY: When the pastry has chilled, line it with a layer of crumpled baking parchment paper or greaseproof paper and a layer of kitchen foil. If you like, weigh down with baking beans, uncooked rice or kitchen weights. Bake in the oven for 15 minutes, then carefully remove the paper and foil and bake for 5 minutes. Next, remove the whole tray from the oven. If there are any holes or cracks in the base, gently patch them with the remaining dough.

ASSEMBLE QUICHE: Chop the spinach finely, then stir the chopped spinach through the egg mixture. Sprinkle half of the grated cheese over the base of the blind-baked case, and sprinkle over the drained broad beans or soybeans. Pour the custard into the case, ensuring it doesn't come too close to the top of the tin, then sprinkle with the remaining cheese and transfer carefully to the oven.

BAKE: Bake for 35-40 minutes until the quiche is a lovely golden brown and the filling has puffed evenly. Remove from the oven and allow to cool before slicing and serving. If the quiche is browning too quickly, reduce the oven temperature to 180°C / 350°F / Gas 4. (see recipe notes)