Mushroom, red onion and tarragon quiche

Instructions

1. First line your tart tin. Lightly grease a 23 cm (9 in) round, 3.5 cm (1½ in) deep tart tin with a little butter. Put the pastry on a lightly floured kitchen bench and roll it out into a large disc 3–4 mm (⅛ in) thick. Gently lay the pastry over the tin, then use your thumb to firmly press the pastry into the base. Trim off the excess pastry with a knife, leaving a little overhanging the edge to allow for shrinkage. Transfer to the fridge to rest for 1 hour.
2. Preheat the oven to 190°C (375°F). Line the rested pastry case with aluminium foil and fill with granulated sugar until heaped. Bake for 30 minutes, then reduce the oven to 160°C (320°F), remove the foil and sugar and bake for a further 20 minutes, or until golden. If you find the middle puffs up, prick the pastry a few times with a fork.
3. Cut the onions in half or thirds (depending on size), leaving the skin on. Trim the top and bottom of each onion so it sits flat, then put the pieces, cut side up, in a roasting tin. Drizzle with 30 g (1 oz/1½ tbsp) of the olive oil and sprinkle the thyme and nigella seeds over the top. Divide 30 g (1 oz) of the butter into small pieces and place on top of each onion piece. Roast for 45 minutes, or until the onion is softened and slightly browned on the edges. Set aside to cool.
4. Use a pastry brush to remove any dirt from the mushrooms, then slice or shred into 3–4 cm (1¼–1½ in) pieces. Melt 20 g (¾ oz) butter with 20 g (¾ oz/1 tbsp) olive oil in a large frying pan over a medium heat. Add half the mushrooms and half the garlic and cook, stirring, until golden brown. Add a squeeze of lemon juice to the pan, then transfer the mushrooms to a colander to drain. Repeat with the remaining mushrooms, garlic and lemon juice, adding more oil and butter as required.
5. To prepare the custard, whisk together the eggs, creme fraiche, milk, salt, pepper, lemon zest and tarragon in a large bowl.
6. Turn the oven back up to 190°C (375°F). Squeeze out any remaining moisture from the mushrooms and scatter them over the base of the tart shell. Remove the skins from the onion halves, then pat off any excess moisture with a clean tea towel (dish towel). Put one onion half, cut side up, in the middle of the quiche, then arrange the remaining onions in a circle around it. Break up the goat’s cheese and scatter it over the mushrooms and in between the onions.
7. Give the custard a stir to evenly disperse the ingredients, then transfer it to a jug to make filling the quiche easier. Slide out your oven shelf, place the tin on the shelf, then pour the custard into the shell, being careful not to overfill it. Or fill it on the bench and carefully transfer to the oven. The custard should fill the spaces around the onions, leaving them visible at the top.
8. Bake for 10 minutes, then reduce the oven to 160°C (320°F). Bake for a further 20–25 minutes, turning the tin halfway through, until the centre of the quiche feels firm but still has a slight wobble. It should be firm rather than runny, but only just cooked. Transfer to a wire rack and cool in the tin for at least 30 minutes to let the custard set. Serve warm or at room temperature. Keeps in the fridge for 3–4 days.