Goat's Cheese, Caramelised Onion and Walnut Quiche

Ingredients

• 200g plain flour
• 100g cold unsalted butter, cubed
• 1 medium egg yolk
• 2-3 tbsp ice-cold water
• 1/2 tsp fine sea salt
• 4 large brown onions (about 700g), thinly sliced
• 30g unsalted butter
• 2 tbsp olive oil
• 4 sprigs fresh thyme, leaves picked
• 1 tbsp soft brown sugar
• 1 tbsp sherry vinegar
• sea salt and black pepper
• 3 large eggs
• 150ml whole milk
• 150ml double cream
• 150g firm goat's cheese (a log with rind), torn into rough chunks
• 1/4 tsp freshly grated nutmeg
• black pepper
• 60g walnut halves, roughly broken
• 1 tsp thyme leaves
• drizzle of olive oil

Method

1. Make the pastry first so it has time to rest. Rub the cold cubed butter into the flour and salt with your fingertips until it looks like coarse breadcrumbs — keep the butter cold, because warm hands melt it into the flour and you lose the short, flaky texture. Stir in the egg yolk and just enough ice-cold water to bring it together into a shaggy dough. Press into a flat disc, wrap, and chill for at least 30 minutes. Resting relaxes the gluten so the pastry won't shrink off the tin walls as it bakes.
2. Now start the onions — they need a full hour and they are the soul of the quiche. Melt the butter with the olive oil in your widest heavy pan over a low heat, add the sliced onions, thyme leaves and a generous pinch of salt. Stir to coat, cover for the first 15 minutes to let them sweat out their water, then lift the lid and cook uncovered, stirring every few minutes. Don't be tempted to crank the heat — you want them to collapse slowly and turn the colour of dark honey, not catch and go bitter. After 50–60 minutes they should be jammy and sticky. Stir in the brown sugar and sherry vinegar, cook 2 more minutes until glossy, then taste and adjust the salt now — onions take more than you'd think. Tip onto a plate to cool.
3. Heat the oven to 190°C fan. Roll the pastry out on a lightly floured surface to about 3mm thick and lift it into a 23cm loose-bottomed tart tin, pressing it gently into the corners without stretching — stretched pastry shrinks back as it bakes. Leave a 1cm overhang to trim later. Prick the base all over with a fork, line with greaseproof and fill with baking beans right up to the rim.
4. Blind bake for 18 minutes, then lift out the paper and beans and bake for another 8–10 minutes until the base looks dry and pale-golden. This second bake is non-negotiable — a damp pastry base goes soggy under the custard. Trim the overhang with a sharp knife while the pastry is still hot. Drop the oven to 160°C fan.
5. Whisk the eggs, milk, cream, nutmeg and a good grind of black pepper in a jug until smooth. Don't add salt to the custard itself — the goat's cheese and onions are already carrying it. Taste a fingertip of the mix: it should taste gently rich and savoury before the cheese even arrives.
6. Spread the cooled onion confit evenly over the pastry base. Dot the goat's cheese chunks across the top — chunks, not crumbles, so you get pockets of molten cheese rather than a uniform layer. Place the tart tin on a baking tray, then pour the custard slowly around the cheese until it reaches just below the pastry rim. Scatter the walnuts and thyme leaves over the top and trickle with a little olive oil so the nuts toast and turn fragrant as the quiche bakes.
7. Bake for 30–35 minutes until the custard is set around the edges but still has a faint wobble in the very centre when you nudge the tray — it will firm up as it cools, and a wobbly middle now means a silky set later rather than a rubbery one. The walnuts should be deep golden and smell toasted.
8. This is the part most people get wrong: let the quiche cool in the tin for at least 30 minutes before slicing. A hot quiche slumps and the custard weeps; a cooled one slices clean with sharp edges.
9. To serve, dress the rocket in a bowl with the extra virgin olive oil, a squeeze of lemon and a pinch of salt — the acid cuts the richness of the cream and goat's cheese in a single stroke. Slice the quiche into generous wedges, pile the dressed rocket alongside, scatter a few cornichons on the board, and tear the baguette into hunks for mopping.